Evolution
4th Edition
ISBN: 9781605356051
Author: Douglas Futuyma, Mark Kirkpatrick
Publisher: SINAUER
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Chapter 14, Problem 2PDT
Summary Introduction
To determine: The specific data required to detect the situation using dN/dS ratio in the case of paralogs and the pattern observed in duplicative loci using the dN /dS ratio.
Introduction: The origin of two or more genes arising from the process of duplication are said to be paralogs. A hemoglobin gene family is composed of many paralogs which are separated in due course of time. The importance of positive selection can be studied with the help of a simple statistical method (dN/dS) comprising of DNA sequences from two different species.
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The ratio of nonsynonymous differences pernonsynonymous site, dN, to synonymous differences per synonymous site, dS, can be usedto test for positive selection Imagine that in a duplicate pair of loci, oneparalog is evolving neutrally while the other isevolving under strong positive selection. Whatspecific data are needed to detect that situationusing the dN/dS ratio, and what pattern do youexpect to see?
What are two reasons why a selection limit is reached in which artificial selection no longer has an effect?
A population of ducks had dull orange bills and an average size of 18 inches from bill to tail. Over time, some researches noticed that the average size of the ducks was still 18 inches, but that now many ducks were either much smaller or much larger and no ducks were actually 18 inches long. The researcher correctly identified that the ducks were undergoing ___A___ selection for size, The researcher also noticed that the bills were a much brighter orange in the ducks, and correctly identified ____B____ selection for bill colouration. A few years later, the researcher returned and noticed that only the male ducks now had bright orange bills and the females were less bright. The researcher hypothesized that ____C____ selection was occurring.
Question 4 options:
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Evolution
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