Introduction to mutation
A mutation is a sudden change in the amount, arrangement or structure of the DNA of an organism. This produces a change in the genotype which may be inherited by cells derived by mitosis or meiosis from the mutant cell.
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Inversion mutation
Inversion occurs when a region of a chromosome breaks off and rotates through 180 degree before rejoining the chromosome. No change in genotype occurs as a result of inversion but phenotypic changes may be seen. This suggests that the order of gene loci on the chromosome is important, a phenomenon known as the position effect. There are varieties of gene mutation involving the addition, loss or rearrangement of bases in the gene. This mutation takes the form of the duplication, insertion, deletion, inversion or substitution of bases. In all this version mutation is a case they change the nucleotide sequence and result in the formation of modified polypeptide.
Heterozygous inversions can pair in meiosis to form an inversion loop. Recombination in an inversion loop produces a duplication of one end of the chromosome and loss of the other, so recombined chromatids do not survive, the exact outcome depends on whether the centromere is inside (pericentric) or outside (paracentric).
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Types of inversion mutation
Para centric inversions
In this case, the inversions have break points on the same side of the centromere. Meiotic recombination in an inversion loop produces one recombined chromatid with two centromeres and another chromatid with lack of centromere.
Pericentric inversions
Pericentric inversions span the centromere and crossover within the inversion loop swaps the ends of one chromatid on each chromosome, duplicating one end and deleting the other and all the chromatics have a single centromere, so they can all segregate normally at meiosis and pass into gametes. Polymorphism for pericentric inversions are not found in Drosophila but are found in other species for example in grasshopper, where the inverted region pairs nonhomologously in meiosis.
A mutation is a sudden change in the amount, arrangement or structure of the DNA of an organism. This produces a change in the genotype which may be inherited by cells derived by mitosis or meiosis from the mutant cell.
I like to share this Electric Circuit Simulator with you all through my article.
Inversion mutation
Inversion occurs when a region of a chromosome breaks off and rotates through 180 degree before rejoining the chromosome. No change in genotype occurs as a result of inversion but phenotypic changes may be seen. This suggests that the order of gene loci on the chromosome is important, a phenomenon known as the position effect. There are varieties of gene mutation involving the addition, loss or rearrangement of bases in the gene. This mutation takes the form of the duplication, insertion, deletion, inversion or substitution of bases. In all this version mutation is a case they change the nucleotide sequence and result in the formation of modified polypeptide.
Heterozygous inversions can pair in meiosis to form an inversion loop. Recombination in an inversion loop produces a duplication of one end of the chromosome and loss of the other, so recombined chromatids do not survive, the exact outcome depends on whether the centromere is inside (pericentric) or outside (paracentric).
Having problem with formula of pressure keep reading my upcoming posts, i will try to help you.
Types of inversion mutation
Para centric inversions
In this case, the inversions have break points on the same side of the centromere. Meiotic recombination in an inversion loop produces one recombined chromatid with two centromeres and another chromatid with lack of centromere.
Pericentric inversions
Pericentric inversions span the centromere and crossover within the inversion loop swaps the ends of one chromatid on each chromosome, duplicating one end and deleting the other and all the chromatics have a single centromere, so they can all segregate normally at meiosis and pass into gametes. Polymorphism for pericentric inversions are not found in Drosophila but are found in other species for example in grasshopper, where the inverted region pairs nonhomologously in meiosis.
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