Method and device for identifying horizontally transferred sequences of recipient insect genomes derived from bacterial genomes

Abstract

The present invention provides a method and apparatus for identifying horizontally transferred sequences from bacterial genomes in recipient insect genomes, relating to the field of biotechnology. The method provided by the present invention for identifying horizontally transferred sequences from bacterial genomes in recipient insect genomes more comprehensively and accurately identifies and analyzes fragments horizontally transferred from a certain type of bacteria to the genome of this species at the whole genome level; based on the horizontally transferred sequence fragments, horizontally transferred genes, gene fragments, and non-coding region fragments are further identified. This provides a comprehensive analysis of horizontal gene transfer between the genomes of a certain eukaryote and a certain type of bacteria, laying a solid, comprehensive, and reliable foundation for further research into the effects of horizontally transferred genes (fragments) on eukaryotes.

Description

Technical Field

[0001] The present invention relates to the field of biotechnology, in particular to a method and device for identifying a horizontal transfer sequence of a recipient insect genome originating from a bacterial genome. Background Art

[0002] With the continuous development and iteration of high-throughput sequencing technology, biological sample DNA processing and extraction technology, and bioinformatics analysis technology, more and more accurate species genomes are being assembled. As the study of genome sequences continues to deepen, research on genes or DNA fragments between the genomes of different species continues to emerge, revealing that genomic gene sequences (fragments) mainly covering bacteria and viral prokaryotes were transferred to the genomes of higher eukaryotes during species evolution, and played an important role in the growth, development, and adaptive evolution of eukaryotes. However, current scientific research results mainly focus on the horizontal transfer of bacterial genes with relatively complete gene structures and can be transcribed.

[0003] Existing technologies, based on random screening of bacterial genes for PCR amplification, can relatively accurately detect whether the amplified bacterial genes (gene fragments) are in the insect genome. However, large-scale PCR amplification of all genes in donor bacteria requires a lot of manpower and time costs; randomly selecting some donor bacterial genes for PCR amplification may miss the detection of a large number of horizontally transferred gene fragments.

[0004] Current research shows that non-coding genes and repetitive sequences in the genome play an important role in the evolution of organisms. Therefore, it is of great significance to comprehensively identify the donor genome sequence fragments (encoding complete genes, non-encoding gene fragments and non-gene regions) horizontally transferred to the recipient at the whole genome level.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The first object of the present invention is to provide a method for identifying horizontally transferred sequences in a recipient insect genome derived from a bacterial genome, so as to solve at least one of the above problems.

[0007] The second object of the present invention is to provide a device for identifying horizontally transferred sequences of a recipient insect genome originating from a bacterial genome.

[0008] A third object of the present invention is to provide a processor.

[0009] In a first aspect, the present invention provides a method for identifying a horizontally transferred sequence of a recipient insect genome derived from a bacterial genome, comprising the following steps:

[0010] a. Use the whole genome alignment software lastz to align the insect genome and bacterial genome, and extract the sequence that matches the bacterial genome;

[0011] b. Using alignment software, align the sequences obtained in step a with the NT database, and classify the sequences into a recipient insect group, other metazoan group, and a non-metazoan outgroup based on the alignment results; the recipient insect group includes species under the classification of metazoa, under the classification of bilaterians, under the phylum Arthropoda, under the class Insecta; the other metazoan group includes other metazoan species except species under the class Insecta;

[0012] c. Calculate the horizontal transfer index (HTI) value for each sequence using the formula HTI = (bestO / bestB) - (bestG / bestB); where bestB is the alignment score of the sequence against the best alignment in the recipient insect group; bestG is the alignment score of the sequence against the best alignment in other metazoan groups; and bestO is the alignment score of the sequence against the best alignment in the non-metazoan outgroup.

[0013] d. Calculate the outO_pct value of each sequence according to the formula outO_pct = number of supporting sequences corresponding to the non-metazoan outgroup / number of supporting sequences corresponding to the NT database; calculate the outWol_pct value of each sequence according to the formula outWol_pct = number of supporting sequences corresponding to the bacterial genome / number of supporting sequences corresponding to the non-metazoan outgroup;

[0014] e. Based on the thresholds HTI>0, outO_pct≥0.6, and outWol_pct>0, screen for horizontally transferred sequences from insect genomes to bacterial genomes;

[0015] f. Extracting the gene sequence or gene fragment sequence from the horizontally transferred sequence obtained in step e, the remaining fragment is the insect genome sequence derived from the non-gene region of the bacterial genome horizontal transfer;

[0016] g. Repeat steps b to e for the gene sequence or gene fragment sequence obtained in step f, and further verify and screen the horizontally transferred genes or gene fragments obtained from the insect genome from the bacterial genome.

[0017] As a further technical solution, in step a, before extracting the sequence matching the bacterial genome, the method also includes: based on the comparison results of step a, using the UCSC database chainNet software tool to construct an insect genome and bacterial genome comparison block, obtaining a maf file, and then extracting the sequence matching the bacterial genome from the maf file.

[0018] As a further technical solution, in step b, the comparison software is blastn.

[0019] As a further technical solution, in step c, the alignment score is obtained using BLAST software.

[0020] As a further technical solution, in step c, if the sequence has no alignment result corresponding to the recipient insect group or other metazoan group or non-metazoan outgroup, bestB or bestG or bestO is defined as 1.

[0021] As a further technical solution, in step d, if the sequence has no alignment result corresponding to the non-metazoan outgroup, outO_pct and outWol_pct are both 0.

[0022] As a further technical solution, step g also includes: obtaining functional annotation information of genes and gene fragments horizontally transferred from the bacterial genome in the insect genome based on the bacterial genome gene annotation information.

[0023] In a second aspect, the present invention provides a device for identifying horizontally transferred sequences of a recipient insect genome derived from a bacterial genome, comprising a first alignment module, a second alignment module, a calculation module, a determination module, and a gene sequence extraction module;

[0024] The first alignment module is used to align the insect genome and the bacterial genome using the whole genome alignment software lastz, and extract sequences that match the bacterial genome;

[0025] The second comparison module is used to compare the sequence derived from the first comparison module or the sequence derived from the gene sequence extraction module with the NT database using comparison software, and classify the sequence into a recipient insect group, other metazoan group, and non-metazoan outgroup according to the comparison result; the recipient insect group includes species under the classification of metazoa, under the classification of bilaterians, under the classification of arthropods, and under the classification of Insecta; the other metazoan group includes other metazoan species except species under the classification of Insecta;

[0026] The calculation module is used to calculate the HTI value of each sequence according to the classification result of the second alignment module according to the formula HTI=(bestO / bestB)-(bestG / bestB); wherein bestB is the alignment score of the best alignment of the sequence corresponding to the recipient insect group; bestG is the alignment score of the best alignment of the sequence corresponding to other metazoan groups; bestO is the alignment score of the best alignment of the sequence corresponding to the non-metazoan outgroup; the outO_pct value of each sequence is calculated according to the formula outO_pct=the number of supporting sequences of the sequence corresponding to the non-metazoan outgroup / the number of supporting sequences of the sequence corresponding to the NT database; the outWol_pct value of each sequence is calculated according to the formula outWol_pct=the number of supporting sequences of the sequence corresponding to the bacterial genome / the number of supporting sequences of the sequence corresponding to the non-metazoan outgroup;

[0027] The determination module is used to screen and obtain horizontally transferred sequences, horizontally transferred genes or gene fragments derived from bacterial genomes in insect genomes based on the threshold values ​​HTI>0, outO_pct≥0.6 and outWol_pct>0;

[0028] The gene sequence extraction module is used to extract the gene sequence or gene fragment sequence in the horizontal transfer sequence obtained by the determination module.

[0029] As a further technical solution, it also includes an annotation module for obtaining functional annotation information of genes or gene fragments horizontally transferred from the bacterial genome in the insect genome based on the bacterial genome gene annotation information.

[0030] In a third aspect, the present invention provides a processor for running a program, wherein the program, when running, executes the above-mentioned method for identifying that the recipient insect genome is derived from the horizontal transfer sequence of the bacterial genome.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The method provided by this invention for identifying horizontally transferred sequences in recipient insect genomes derived from bacterial genomes allows for a more comprehensive and accurate analysis of fragments horizontally transferred from a particular bacterial species to the genome of that species at the whole genome level. Based on these fragments, the method further identifies horizontally transferred genes, gene fragments, and non-coding region fragments. This method provides a comprehensive analysis of horizontal gene transfer between the genomes of a certain eukaryote and a certain bacterial species, laying a solid, comprehensive, and reliable foundation for further research into the effects of horizontally transferred genes (fragments) on eukaryotes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a technical flow chart provided for Example 1 of the present invention. DETAILED DESCRIPTION

[0035] Below in conjunction with embodiment and example, embodiment of the present invention is described in detail, but those skilled in the art will appreciate that the following embodiment and example are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiment in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise all fall within the scope of protection of the present invention. Unspecified conditions are carried out according to the conditions of normal conditions or manufacturer's recommendations. Reagents used or instruments not specified by the manufacturer are conventional products that can be purchased commercially.

[0036] In a first aspect, the present invention provides a method for identifying a horizontally transferred sequence of a recipient insect genome derived from a bacterial genome, comprising the following steps:

[0037] a. Use the whole genome alignment software lastz to align the insect genome and bacterial genome, and extract the sequence that matches the bacterial genome;

[0038] b. Using alignment software, align the sequences obtained in step a with the NT database, and classify the sequences into a recipient insect group, other metazoan group, and a non-metazoan outgroup based on the alignment results; the recipient insect group includes species under the classification of metazoa, under the classification of bilaterians, under the phylum Arthropoda, under the class Insecta; the other metazoan group includes other metazoan species except species under the class Insecta;

[0039] c. Calculate the HTI value for each sequence using the formula HTI = (bestO / bestB) - (bestG / bestB); where bestB is the alignment score of the sequence against the best alignment in the recipient insect group; bestG is the alignment score of the sequence against the best alignment in other metazoan groups; and bestO is the alignment score of the sequence against the best alignment in the non-metazoan outgroup.

[0040] d. Calculate the outO_pct value for each sequence using the formula outO_pct = number of supporting sequences for the sequence corresponding to the non-metazoan outgroup / number of supporting sequences for the sequence corresponding to the NT database; calculate the outWol_pct value for each sequence using the formula outWol_pct = number of supporting sequences for the sequence corresponding to a specific bacterial genome / number of supporting sequences for the sequence corresponding to the non-metazoan outgroup;

[0041] e. Based on the thresholds HTI>0, outO_pct≥0.6, and outWol_pct>0, screen for horizontally transferred sequences from insect genomes to bacterial genomes;

[0042] f. Extracting the gene sequence or gene fragment sequence from the horizontally transferred sequence obtained in step e, the remaining fragment is the insect genome sequence derived from the non-gene region of the bacterial genome horizontal transfer;

[0043] g. Repeat steps b to e for the gene sequence or gene fragment sequence obtained in step f, and further verify and screen the horizontally transferred genes or gene fragments obtained from the insect genome from the bacterial genome.

[0044] The present invention is based on a whole-genome alignment scheme and uses lastz software to perform whole-genome alignment of insect genomes and bacterial genomes. Compared with blast alignment, the present invention can span more alignment gap regions and obtain similar sequence segments at the whole-genome level of species with different genetic relationships, laying a solid foundation for the comprehensive and accurate identification of horizontally transferred genes, gene fragments and non-gene regions; the present invention identifies horizontally transferred sequence segments derived from bacterial genomes in insect genomes, which has not been proposed in existing schemes and studies; compared with previous studies, the present invention only identifies and analyzes whether existing annotated genes in insect genomes are derived from horizontal gene transfer in bacterial genomes, while the present annotated genes and unannotated genes in insect genomes are identified and analyzed at the whole-genome level, and incomplete gene fragments of horizontal transfer are identified; the present invention clearly proposes the identification of bacteria as the specific source of horizontally transferred genes (gene fragments) in insect genomes.

[0045] In some optional embodiments, in step a, before extracting the sequence matching the bacterial genome, the method further includes: based on the comparison results of step a, using the UCSC database chainNet software tool to construct an insect genome and bacterial genome comparison block to obtain a maf file, and then extracting the sequence matching the bacterial genome from the maf file.

[0046] The UCSC database chainNet software tools include axtChain, chainMergeSort, chainPreNet, chainNet, netSyntenic, netToAxt, axtSort, and axtToMaf.

[0047] It should be noted that the maf file includes the start position and end position information of the comparison block.

[0048] In some optional embodiments, in step b, the comparison software is blastn.

[0049] In some optional embodiments, in step c, a score is performed based on the alignment consistency. The higher the alignment consistency, the higher the score. In the present invention, the alignment score is preferably obtained using BLAST software.

[0050] In some optional embodiments, in step c, if the sequence has no alignment result corresponding to the recipient insect group or other metazoan group or non-metazoan outgroup, bestB or bestG or bestO is defined as 1.

[0051] In some optional embodiments, in step d, if the sequence has no alignment result corresponding to the non-metazoan outgroup, outO_pct and outWol_pct are both 0.

[0052] In some optional embodiments, step g further includes: obtaining functional annotation information of genes and gene fragments horizontally transferred from the bacterial genome in the insect genome based on the bacterial genome gene annotation information.

[0053] In a second aspect, the present invention provides a device for identifying horizontally transferred sequences of a recipient insect genome derived from a bacterial genome, comprising a first alignment module, a second alignment module, a calculation module, a determination module, and a gene sequence extraction module;

[0054] The first alignment module is used to align the insect genome and the bacterial genome using the whole genome alignment software lastz, and extract sequences that match the bacterial genome;

[0055] The second comparison module is used to compare the sequence derived from the first comparison module or the sequence derived from the gene sequence extraction module with the NT database using comparison software, and classify the sequence into a recipient insect group, other metazoan group, and non-metazoan outgroup according to the comparison result; the recipient insect group includes species under the classification of metazoa, under the classification of bilaterians, under the classification of arthropods, and under the classification of Insecta; the other metazoan group includes other metazoan species except species under the classification of Insecta;

[0056] The calculation module is used to calculate the HTI value of each sequence according to the classification result of the second alignment module according to the formula HTI=(bestO / bestB)-(bestG / bestB); wherein bestB is the alignment score of the best alignment of the sequence corresponding to the recipient insect group; bestG is the alignment score of the best alignment of the sequence corresponding to other metazoan groups; bestO is the alignment score of the best alignment of the sequence corresponding to the non-metazoan outgroup; the outO_pct value of each sequence is calculated according to the formula outO_pct=the number of supporting sequences of the sequence corresponding to the non-metazoan outgroup / the number of supporting sequences of the sequence corresponding to the NT database; the outWol_pct value of each sequence is calculated according to the formula outWol_pct=the number of supporting sequences of the sequence corresponding to a specific bacterial genome / the number of supporting sequences of the sequence corresponding to the non-metazoan outgroup;

[0057] The determination module is used to screen and obtain horizontally transferred sequences, horizontally transferred genes or gene fragments derived from bacterial genomes in insect genomes based on the threshold values ​​HTI>0, outO_pct≥0.6 and outWol_pct>0;

[0058] The gene sequence extraction module is used to extract the gene sequence or gene fragment sequence in the horizontal transfer sequence obtained by the determination module.

[0059] The device provided by the present invention can identify the codable genes, gene fragments and non-gene region sequences in a certain insect genome that are horizontally transferred from a certain bacterial genome, and provide comprehensive markers for studying the horizontal transfer sequences of a certain insect genome from a certain bacterial genome.

[0060] In some optional embodiments, an annotation module is further included for obtaining functional annotation information of genes or gene fragments horizontally transferred from the bacterial genome in the insect genome based on the bacterial genome gene annotation information.

[0061] In some optional embodiments, in the first comparison module, before extracting the sequence matching the bacterial genome, the method further includes: based on the comparison results, using the UCSC database chainNet software tool to construct an insect genome and bacterial genome comparison block to obtain a maf file, and then extracting the sequence matching the bacterial genome from the maf file.

[0062] The UCSC database chainNet software tools include axtChain, chainMergeSort, chainPreNet, chainNet, netSyntenic, netToAxt, axtSort, and axtToMaf.

[0063] It should be noted that the maf file includes the start position and end position information of the comparison block.

[0064] In some optional embodiments, in the second alignment module, the alignment software is blastn.

[0065] In some optional embodiments, in the calculation module, a score is performed based on the alignment consistency. The higher the alignment consistency, the higher the score. In the present invention, the alignment score is preferably obtained using BLAST software.

[0066] In some optional embodiments, in the calculation module, if the sequence has no alignment result corresponding to the recipient insect group or other metazoan group or non-metazoan outgroup, bestB or bestG or bestO is defined as 1.

[0067] In some optional embodiments, in the calculation module, if the sequence has no alignment result corresponding to the non-metazoan outgroup, outO_pct and outWol_pct are both 0.

[0068] In a third aspect, the present invention provides a processor for running a program, wherein the program, when running, executes the above-mentioned method for identifying that the recipient insect genome is derived from the horizontal transfer sequence of the bacterial genome.

[0069] The processor provided by the present invention can identify the horizontally transferred codable genes, gene fragments and non-gene region sequences in a certain insect genome that are derived from a certain bacterial genome.

[0070] The present invention is further described below by way of specific examples. However, it should be understood that these examples are merely provided for more detailed description and are not to be construed as limiting the present invention in any form.

[0071] Example 1

[0072] Take the horizontal transfer gene (fragment) of an insect genome from the Wolbachia genome as an example, Figure 1 As shown, the identification and analysis process is as follows:

[0073] The insect genome is labeled as insect-genome and the Wolbachia genome is labeled as wolbachia-genome.

[0074] 1) Based on the insect-genome and wolbachia-genome, the whole genome alignment software lastz was used to align the insect-genome and wolbachia-genome, with the following parameters: M=254K=4500L=3000Y=15000E=150H=2000O=600T=2;

[0075] 2) Based on the alignment results from 1), the UCSC database chainNet software tools (axtChain, chainMergeSort, chainPreNet, chainNet, netSyntenic, netToAxt, axtSort, and axtToMaf) were used to construct the insect-genome and wolbachia-genome alignment blocks and convert them into a maf file labeled insect_wolbachia.maf. Default parameters were used.

[0076] 3) Based on the maf file insect_wolbachia.maf in 2), extract the sequence corresponding to the insect-genome in the block;

[0077] 4) Based on the sequences corresponding to the insect-genome in the blocks extracted in 3), the blastn software was used to compare with the NT (NCBI, non-redundant nucleic acid database) database, and the application parameters were: -task blastn -short -word_size7 -evalue 1 -max_target_seqs 1000;

[0078] 5) Based on the comparison results in 4) and the taxonomic library of each sequence in the NT database, each comparison result is matched to a biological classification, corresponding to the taxonomic level covering kingdom, phylum, class, order, family, genus, and species;

[0079] 6) Based on the results of 5), the alignment results were divided into three groups: insect group-receptor group (RECIPIENT), other metazoan group (GROUP), and non-metazoan outgroup (OUTGROUP);

[0080] 7) Based on the results of 6), the best alignment corresponding to the insect group-receptor group (RECIPIENT) of each sequence is extracted, and the bitscore value of this best alignment is marked as bestB, the best alignment corresponding to other metazoan groups (GROUP) is marked as bestG, and the best alignment corresponding to the non-metazoan outgroup (OUTGROUP) is marked as bestO. The HTI value of each sequence is calculated according to the formula HTI = (bestO / bestB) - (bestG / bestB), where for sequences without an alignment result corresponding to the insect group-receptor group (RECIPIENT) or metazoan group (GROUP) or non-metazoan outgroup (OUTGROUP), the bitscore value bestB, bestG, or bestO is defined as 1;

[0081] 8) Based on the results of 6), the percentage value outO_pct of each sequence corresponding to the non-metazoan outgroup (OUTGROUP) of all alignment results and the percentage value outWol_pct of the sequence corresponding to Wolbachia "Wolbachia" of the non-metazoan outgroup (OUTGROUP) alignment results were calculated respectively. For sequences without corresponding non-metazoan outgroup (OUTGROUP) alignment results, both outO_pct and outWol_pct were 0;

[0082] 9) Based on the results of 7) and 8), the insect genome was screened for wolbachia-genome horizontal transfer sequences based on the thresholds HTI>0, outO_pct≥0.6, and outWol_pct>0. The thresholds HTI>0 and outO_pct≥0.6 define the insect genome as being derived from non-metazoan outgroup (OUTGROUP) horizontal transfer sequences. Based on the above, certain insect genomes were derived from genomic horizontal transfer sequences and from the Wolbachia genome.

[0083] 10) Based on the insect-genome obtained by screening in 9), the horizontal transfer sequence derived from the non-metazoan outgroup (OUTGROUP), the alignment file insect_wolbachia.maf, and the Wolbachia genome gene annotation information, the sequence corresponding to the insect gene position information is obtained, which is the candidate insect genome derived from the Wolbachia genome horizontal transfer gene (gene fragment sequence).

[0084] 11) Based on the candidate insect genomes obtained from the screening in 10), the genes (gene fragment sequences) horizontally transferred from the Wolbachia genome were compared with the NT database using blastn alignment software, and steps 5), 6), 7), 8), and 9) were repeated to further verify that the insect genomes were derived from genes and gene fragments horizontally transferred from the Wolbachia genome;

[0085] 12) Based on the gene annotation information of the Wolbachia genome, obtain the functional annotation information of the horizontally transferred genes and gene fragments from the Wolbachia genome in the insect genome.

[0086] Based on the above analysis method, a genome of one Anoplophora genus and one Monochamus genus, as well as the genome of Wolbachia, a symbiont of Drosophila melanogaster, were used to analyze the horizontally transferred sequences of the Anoplophora and Monochamus genus genomes from the Wolbachia genome. The results showed that the Anoplophora genus contained 1175 base pairs of horizontally transferred sequences from the Wolbachia genome, accounting for 0.000166% of the genome, while the Monochamus genus contained 248,948 base pairs of horizontally transferred sequences from the Wolbachia genome, accounting for 0.0297% of the genome. A chi-square test showed that the horizontally transferred sequences from the Wolbachia genome in the Anoplophora and Monochamus genus genomes were significantly different (P < 2.2e-16). Literature review showed that Monochamus genus genomes contain a large number of horizontally transferred sequences from the Wolbachia genome, while these sequences are rarely reported in Anoplophora genus. At the same time, existing studies have shown using PCR amplification methods that genes (or gene fragments) horizontally transferred from the Wolbachia genome in the Monochamus alternatus genome vary between populations and between individuals within a population. 34 Wolbachia genes were amplified, of which 24 genes (gene fragments) were commonly found in Monochamus alternatus individuals. Our analysis showed that 135 genes (gene fragments) were identified, of which 18 of the 24 PCR amplifications in the literature covered about 75%. In addition, we identified that the Wolbachia genome has 27 genes, and that fragments of the same gene are inserted into different locations in the Monochamus alternatus genome. The above comparative studies show that the results of the present invention are reliable and can more comprehensively and accurately identify genes (gene fragments) horizontally transferred from a certain bacterial genome in the insect genome, as well as non-gene region sequences.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying horizontally transferred sequences of a recipient insect genome derived from a bacterial genome, characterized in that: The following steps are involved: a. Use the whole genome alignment software lastz to align the insect genome and bacterial genome, and extract sequences that match the bacterial genome; b. Using alignment software, align the sequences obtained in step a with the NT database, and classify the sequences into a recipient insect group, other metazoan group, and a non-metazoan outgroup based on the alignment results; the recipient insect group includes species within the Metazoa classification, the Bilaterian classification, the Arthropoda classification, the Insecta classification, and the Other Metazoa group includes other metazoan species excluding species within the Insecta classification; c. Calculate the HTI value for each sequence using the formula HTI = (bestO / bestB) - (bestG / bestB); where bestB is the alignment score of the sequence against the best alignment in the recipient insect group; bestG is the alignment score of the sequence against the best alignment in other metazoan groups; and bestO is the alignment score of the sequence against the best alignment in the non-metazoan outgroup. d. Calculate the outO_pct value for each sequence using the formula outO_pct = number of supporting sequences corresponding to the non-metazoan outgroup / number of supporting sequences corresponding to the NT database; calculate the outWol_pct value for each sequence using the formula outWol_pct = number of supporting sequences corresponding to the bacterial genome / number of supporting sequences corresponding to the non-metazoan outgroup; e. Based on the thresholds HTI>0, outO_pct≥0.6, and outWol_pct>0, the horizontally transferred sequences from insect genomes to bacterial genomes were screened; f extracting the gene sequence or gene fragment sequence obtained in step e horizontal transfer sequence, the remaining fragment is the insect genome sequence derived from the bacterial genome horizontal transfer non-gene region; g. Repeat steps b to e for the gene sequence or gene fragment sequence obtained in step f to further verify the screening of insect genomes derived from bacterial genomes for horizontal transfer of genes or gene fragments; In step a, before extracting the sequence matching the bacterial genome, the following steps are also included: based on the alignment results of step a, using the UCSC database chainNet software tool to construct an insect genome and bacterial genome alignment block to obtain a maf file, and then extracting the sequence matching the bacterial genome from the maf file; The method further includes, after step g: obtaining functional annotation information of genes and gene fragments horizontally transferred from the bacterial genome in the insect genome based on the bacterial genome gene annotation information.

2. The method according to claim 1, characterized in that In step b, the comparison software is blastn.

3. The method according to claim 1, characterized in that In step c, the alignment score is obtained using BLAST software.

4. The method according to claim 1, wherein In step c, if the sequence has no alignment results corresponding to the recipient insect group or other metazoan groups or non-metazoan outgroups, bestB, bestG, or bestO is defined as 1.

5. The method according to claim 1, characterized in that In step d, if the sequence has no alignment results corresponding to the non-metazoan outgroup, outO_pct and outWol_pct are both 0.

6. A device for identifying horizontally transferred sequences of a recipient insect genome derived from a bacterial genome, characterized in that: The device performs the method for identifying a horizontally transferred sequence of a recipient insect genome derived from a bacterial genome as described in claim 1, comprising a first alignment module, a second alignment module, a calculation module, a determination module, and a gene sequence extraction module; The first alignment module is used to align the insect genome and the bacterial genome using the whole genome alignment software lastz. Based on the alignment results, the UCSC database chainNet software tool is used to construct the insect genome and bacterial genome alignment blocks to obtain the maf file, and then extract the sequence matching the bacterial genome from the maf file; The second comparison module is used to compare the sequence derived from the first comparison module or the sequence derived from the gene sequence extraction module with the NT database using comparison software, and classify the sequence into a recipient insect group, other metazoan group, and non-metazoan outgroup according to the comparison result; the recipient insect group includes species under the classification of metazoa, under the classification of bilaterians, under the classification of arthropods, and under the classification of Insecta; the other metazoan group includes other metazoan species except species under the classification of Insecta; The calculation module is used to calculate the HTI value of each sequence according to the classification result of the second alignment module according to the formula HTI=(bestO / bestB)-(bestG / bestB); wherein bestB is the alignment score of the best alignment of the sequence corresponding to the recipient insect group; bestG is the alignment score of the best alignment of the sequence corresponding to other metazoan groups; bestO is the alignment score of the best alignment of the sequence corresponding to the non-metazoan outgroup; the outO_pct value of each sequence is calculated according to the formula outO_pct=the number of supporting sequences of the sequence corresponding to the non-metazoan outgroup / the number of supporting sequences of the sequence corresponding to the NT database; the outWol_pct value of each sequence is calculated according to the formula outWol_pct=the number of supporting sequences of the sequence corresponding to the bacterial genome / the number of supporting sequences of the sequence corresponding to the non-metazoan outgroup; The determination module is used to screen and obtain horizontally transferred sequences, horizontally transferred genes or gene fragments derived from bacterial genomes in insect genomes based on the threshold values ​​HTI>0, outO_pct≥0.6 and outWol_pct>0; The gene sequence extraction module is used to extract the gene sequence or gene fragment sequence in the horizontal transfer sequence obtained by the determination module; It also includes an annotation module for obtaining functional annotation information of genes or gene fragments horizontally transferred from the insect genome to the bacterial genome based on the bacterial genome gene annotation information.

7. A processor, characterized in that: The processor is used to run a program, wherein the program, when running, executes the method for identifying a horizontally transferred sequence of a recipient insect genome derived from a bacterial genome according to any one of claims 1 to 5.

Images