explain why is the first choice correct and the second one is not: You sequenced
ID: 3363149 • Letter: E
Question
explain why is the first choice correct and the second one is not:
You sequenced a population and a related species for a gene. You note the following patterns:
Nonsynonymous changes synonymous changes
Within species 17 82
Between species 36 125
(a): which test of neutrality are you employing? (c) The McDonald-Kreitman test. NOT (b) the HKA test.
(b): is the data significant? (b) No.
(c): if the test was significant, what does that tell you? (e) Selection is acting differently within vs. between species. NOT (a) positive selection
Explanation / Answer
Between species Within species
Nonsynonymous 36 17
Synnonmyous 125 82
If ratio of non- nonsynonymous / synonymous (between species) > = non- nonsynonymous / synonymous (within species)
Then we can inference that, increased non- nonsynonymous / synonymous (between species) changes between species that is positive selection
As in this question this ratio= 0.28> 0.20
So, there is positive selection. Since this ratio is v
In this question, The McDonald–Kreitman (MK) test is used because it relates the ratio of non- synonymous and synonymous mutations between and within species. In general , the use of HKA tests has been restricted because of the nonexistence of putatively neutral loci.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.