Discussion Topic Essay Example | Topics and Well Written Essays - 500 words - 5

Discussion Topic - Essay Example Two common genes that undergo mutation to result in achromatopsia are CNGB3 and CNGA3. Four chromosomes might have changes responsible for achromatopsia. These chromosomes are chromosome 14, chromosome 8q21-q22, chromosome 2q11, and chromosome 10q24. A mutation that causes this disorder was discovered through a comparative positional cloning approach. The locus of the disorder is in a region of chromosome CFA29. The homologous region on the human genome has the gene for cyclic nucleotide-gated channel beta subunit. Mutation causes same disorders in human beings. The mode of inheritance for this disorder is autosomal recessive. Some chromosomal information is lost or deleted through the process of converting DNA to amino acids (Parker, 2004). A scientist known as Punnet in 1993 discovered the trait for blue egg. This trait was mapped on chromosome GGA1 to a region from 67.3-69.1. Dongxiang chicken breed was used to discover this trait. Using analysis of linkage on the candidate region on information from 146 F2 hens that originate from cross breeding between homozygous blue and homozygous non-blue birds of the Dongxiang breed, scientists refined the location to 120 kb region from 67296991 bp to 67416784 bp located on chromosome 1along the chicken genome. The location that was refined by scientists is made up of four positional candidate genes. Just a single gene out of the four genes is responsible for blue shell trait. This gene is SLCO1B3. It is expressed in the shell glands in the uterus of chicken with a blue shell trait but it is not expressed in shell glands within the uterus of non blue-shelled hens. Through the process of converting DNA to proteins, a gene responsible for this trait was inserted within the amino acid sequence in the protein structure. Process of sequencing uncovered causal mutation to be a~4.2, (that is a retroviral), EAV-HP in the fifth flanking region of SLCO1B3. A survey for genotyping