Method for extracting DNA from formalin fixed hair

A technology of formalin and hair, applied in DNA preparation, recombinant DNA technology, sugar derivatives, etc., can solve problems such as long soaking time in antiseptic solution, difficulty in extracting genetic material, and reduced activity of active sites, etc., to achieve shortening The time and method of hair digestion are efficient and the effect of increasing the surface area

Inactive Publication Date: 2009-07-29
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in archaeological and forensic identification, it is often found that the hair follicles have been lost too late, or the hair root has been destroyed due to the long soaking time in the embalming solution
It is relatively difficult to extract genetic material from the hair shaft
At present, there have been reports of genome extraction from fresh hair shafts, and reports of genome extraction from tissue specimens that have been temporarily soaked and fixed, but there is no successful example of genome extraction from hair shafts that have been soaked and fixed for a long time. The stem is keratinized tissue, the main component is protein, and part of the hair shaft is difficult to digest; on the other hand, formalin not only binds to the amino group of the protein, which reduces or loses the activity of the active site, but also promotes DNA- DNA cross-linking and DNA-protein cross-linking lead to DNA fragmentation and difficulty in extraction

Method used

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  • Method for extracting DNA from formalin fixed hair

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] Take the hair shaft 20cm away from the hair follicle 2cm away from the formalin fixed hair for 10 years, wash it thoroughly with detergent to remove all impurities on the hair, rinse it with sterile distilled water several times, and then use sterile 2.0% Wash with NaOH for 5 minutes, then wash with sterile 2.0% HCl for 5 minutes, then rinse with sterile distilled water for at least 3 times, and then wash with 75% and absolute ethanol one time, and then dry for use.

[0010] Dry the hair in a homogenizer containing 300μl of sodium citrate repair solution with a pH of 6.0 and a concentration of 0.01mmol / L at 2°C. Only when the dry hair fragments are invisible to the naked eye, transfer the grinding solution to In a new EP tube with a sterilization volume of 2ml, the homogenizer was washed twice with an equal volume of fresh repair solution and transferred to the EP tube, and then repaired in a boiling water bath for 8 minutes. After the repair is completed, add an equal volu...

Embodiment 2

[0016] Take formalin-fixed hair for 30 years, take 2cm away from the hair follicle and cut the hair shaft 20cm, first wash it thoroughly with detergent to remove all impurities on the hair, rinse with sterile distilled water for 8 times, and then use sterile Wash with 2.0% NaOH for 5 minutes, then wash with sterile 2.0% HCl for 5 minutes, then rinse with sterile distilled water for at least 3 times, and then wash with 75% and absolute ethanol one time, and then dry for use.

[0017] Preparation and treatment of restoration samples: Dry the hair in a homogenizer containing 300μl of sodium citrate restoration solution with a pH of 6.0 and a concentration of 0.01mmol / L. The dry fragments of the hair can not be seen with the naked eye. , Transfer the grinding liquid to a new EP tube with a sterilization volume of 2ml, wash the homogenizer twice with an equal volume of fresh repair liquid and transfer them to the EP tube, and then repair in a boiling water bath for 15 minutes. After th...

Embodiment 3

[0021] From Muyi hair in the Qing Dynasty, 300 years ago, take the hair shaft 20cm away from the hair follicle in the hair, wash it thoroughly with detergent, remove all impurities on the static hair, rinse it with sterile distilled water several times, and then use it. The bacteria are washed with 2.0% NaOH for 5 minutes, then washed with sterile 2.0% HCl for 5 minutes, then rinsed with sterile distilled water for at least 3 times, washed with 75% and absolute ethanol, and then dried for use. .

[0022] Preparation and treatment of restoration samples: Dry the hair in a homogenizer containing 300μl of sodium citrate restoration solution with a pH of 6.0 and a concentration of 0.01mmol / L at 5°C and grind until no dry hair fragments can be seen with the naked eye , Transfer the grinding liquid to a new 2ml EP tube, the homogenizer is washed twice with an equal volume of fresh repair liquid and transferred to the EP tube, and then repaired in a boiling water bath for 5 minutes. Afte...

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Abstract

The invention discloses a method of extracting DNA from formalin-fixed hair stems. After washing and pretreatment, the hair stems are put into a homogenizer full of 0.01mmol / L sodium citrate solution for grinding under 0 to 10 DEG C, then put in boiling water bath for 5 to 15min and be restored; ethanol is added for stewing, then eccentrically collected and deposited; hair digestive fluid and proteinase K solution are added into the deposition, and continuously digested for 1 to 2 hours in water bath at the temperature of 37-57 DEG C; DNA is extracted after digestion. The invention restores hair stem samples so as to totally or partially recover the activity of the protein active site. In addition, the preparation of the digestive fluid takes the characteristics of hair stem crack into full consideration so as to greatly improve the efficiency of hair stem crack and shorten the time of hair digestion. The method is used to extract not only the genome in the hair stem soaked in formalin but also the genome in the ancient hair stem.

Description

Technical field [0001] The invention relates to a method for extracting DNA from a special hair shaft. Background technique [0002] In the field of biomedicine, formalin is often used for antiseptic fixation of animal tissue specimens, medical cadavers and pathological tissue specimens. It has been reported in the literature that formalin will damage the genetic information of the fixed specimen tissue to a certain extent, and the longer the soaking and fixation time, the greater the damage to DNA. [0003] Hair is divided into two parts, hair shaft and hair root. The main component is keratin, including fibrin and cystine-rich non-helical protein. It is this keratin structure that makes it non-perishable, so it is in ancient tomb remains. During the cleaning process, most of the remains of the tomb owners only left hair and bones. At the same time, hair is also one of the commonly used evidences for forensic identification. When using hair for genetic material extraction, the r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07H21/04C12N15/10
Inventor 黄菊芳曾乐平陈旦童建斌王慧罗学港
Owner CENT SOUTH UNIV
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