DNA-sequencing studies for a gene in populations of two closely related species
ID: 69749 • Letter: D
Question
DNA-sequencing studies for a gene in populations of two closely related species produce the following numbers of sites that vary:
Synonymous polymorphisms
50
Nonsynonymous polymorphisms
20
Nonsynonymous species differences
2
Synonymous species differences
18
Does this result support a neutral evolution of the gene? Does it support and adaptive replacement of amino acids? What explanation would you offer for the observations?
Please answer this question COMPLETELY and I will be sure to "thumbs up" your answer! Thank you!
Synonymous polymorphisms
50
Nonsynonymous polymorphisms
20
Nonsynonymous species differences
2
Synonymous species differences
18
Explanation / Answer
Synonymous SNP is the one that changes codon within the amino acid and non synonymous SNP is the one that changes the codon between amino acid.
For a neutral evolution of a gene the ratio of variable synonymous polymorphism must be equal to non synonymous differences between species.
Adaptive replacement of amino acids occur as a result of increased non synonymous divergence between .species.
No of synonymous difference within polymorphs/ No of non synonymous difference within polymorphism =
No of synonymous difference between species / No of non-synonymous difference between species
50/20 = 2/18 where
2.5 = 0.11
No of synonymous difference between species / No of non-synonymous difference between species is far less than No of synonymous difference within polymorphs/ No of non synonymous difference within polymorphism . It favors adaptive replacement of amino acids
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.