Beef Cattle ACTN3 Gene Modification for Muscle Fiber Shift
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Solution Overview
Problem
Bovine cattle have inefficient muscle fiber composition due to the dominance of Type II skeletal muscle fibers, leading to poor feed conversion ratios, tough meat, and increased environmental emissions, as the Alpha-actinin-3 protein promotes energy inefficiency and excessive Type II fiber development.
Innovation Solution
Genetic modification of the ACTN3 gene to reduce or eliminate the expression of the Alpha-actinin-3 protein, shifting the muscle fiber composition towards more efficient Type I fibers, achieved through methods like CRISPR and TALENs, which alter the chromosomal sequence to introduce premature termination codons or frameshift mutations, thereby reducing the number and size of Type II fibers and increasing the proportion of Type I fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ACTN3 gene is fully expressed to produce Alpha-actinin-3 protein, then Type II skeletal muscle fibers are abundant with greater contractile force, but feed conversion ratio deteriorates and energy efficiency decreases
Solution Approach 1:
The invention extracts and removes the harmful function of the ACTN3 gene by introducing mutations (premature termination codons or frameshift mutations) that eliminate or reduce Alpha-actinin-3 protein production. This extraction of the problematic protein synthesis function resolves the contradiction by eliminating the energy inefficiency while preserving the muscle fiber composition shift toward Type I fibers.
Solution Approach 2:
The invention changes the genetic parameter of the ACTN3 gene by introducing specific mutations (nonsense mutations or frameshift mutations) that alter the protein expression level. This parameter change in the gene sequence transforms the muscle fiber composition from Type II-dominant to Type I-dominant, thereby improving energy efficiency while maintaining adequate contractile function through the shifted fiber type composition.
2Force
If Type II skeletal muscle fibers are predominant, then greater contractile force is generated during life, but meat quality deteriorates with reduced sarcomere length and increased toughness
Solution Approach 1:
The invention extracts the problematic effect of Type II fiber predominance on meat quality by eliminating Alpha-actinin-3 production. This removal of the protein that maintains Type II fiber characteristics allows the muscle to develop Type I fiber predominance, which naturally produces meat with better sarcomere length and tenderness, thereby resolving the meat quality issue.
Solution Approach 2:
Instead of trying to improve meat quality within Type II fibers, the invention inverts the approach by shifting the entire muscle fiber composition toward Type I fibers through ACTN3 gene modification. This inversion of the fiber type distribution fundamentally changes the meat quality characteristics in a beneficial direction, producing more tender and palatable meat.
3Productivity
If Type I skeletal muscle fibers are increased through ACTN3 elimination, then feed conversion ratio improves and energy efficiency increases, but contractile force during life is reduced
Solution Approach 1:
The invention changes the genetic parameter of muscle fiber composition by eliminating ACTN3 expression, which shifts the muscle fiber type distribution toward Type I predominance. This parameter change in fiber composition improves feed conversion ratio and energy efficiency. The system accepts a moderate reduction in contractile force as a trade-off for the significant improvement in productivity and energy efficiency.
4Stability of the object's composition
If Alpha-actinin-3 protein is produced, then Type II muscle fibers are maintained, but environmental emissions increase due to poor feed efficiency
Solution Approach 1:
The invention extracts the harmful environmental impact by eliminating Alpha-actinin-3 protein production through ACTN3 gene modification. This extraction of the protein synthesis function shifts muscle fiber composition toward Type I, which improves feed conversion efficiency and thereby reduces greenhouse gas emissions and other environmental harms associated with inefficient feed utilization.
Data Source
AI summary
A bovine animal or offspring thereof or a bovine cell or gene comprising a modified chromosomal sequence in at least one allele of a gene encoding an Alpha-actinin-3 protein, wherein said modified chromosomal sequence partially or completely impairs the ability of said animal/cell/gene to encode said protein. The bovine retains all previous functionality, but is distinguished by a reduction in the number and cross-sectional area of Type II muscle fibers, and an increase in the proportion of Type I muscle fibers, resulting in improved feedlot efficiency, improved meat quality, and reduced emissions output.