GENETICS MAJORS ONLY PLEAASE, DO NOT COPY AND PASTE THE ANSWER ON THIS SITE ALRE
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Question
GENETICS MAJORS ONLY PLEAASE, DO NOT COPY AND PASTE THE ANSWER ON THIS SITE ALREADY, AS IT WAS INCORRECT!!!!!!!!!
Question: Heterozygotes may or may not be indistinguishable from a homozygote.
a) compare the enzyme (molecular) and whole-body (general) phenotypes of heterozygotes for Tay-Sachs disease to heterozygotes for AB blood type.
b) describe if and how the following terms apply to Tay-Sachs disease and to ABO blood type: pleiotropy, multiple alleles, genetic heterogeneity. (3 marks)
Explanation / Answer
A)Humans with Tay-Sachs disease lack a enzyme Hexo-sa-minidase A which is essential to metabolize some lipids. These lipids accumulate in the brain which results in death.Offspring with two Tay-Sachs alleles (homozygotes) have the disease ie irecessive character is present.Both heterozygotes with one allele which is working and homozygotes with two working alleles are healthy and normal.At the biochemical level, the alleles show incomplete dominance in heterozygotes.Heterozygous individuals produce equal numbers of normal and dysfunctional enzyme molecules.The Tay-Sachs and functional alleles are codominant at the molecular level
The heterozygous phenotype results when both the alleles express themselves.The ABO blood group is determined by three alleles IA, IB and i.Here, IA and IB alleles are co dominant to each other whereas both the IA and IB alleles are dominant to the allele i.There are six possible genotypes and four possible blood types because two alleles are present in each individual.Individuals whove have-
B)Pleiotrophy-Single gene is responsible for different traits.Both these Tay Sachs disease and AB blood group both are not example of pleiotrpy as its expression depends on presence of two alleles.
Multiple alleles is when a trait is controlled by more than 2 alleles. ABO blood group is a example of this as it does not have three alleles ie. ABO.
Genetic Heterogeneity-In which different genes can produce identical phenotypes.It is also absent in both. All the conditions in both are explained that in what conditions they will express itself.
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