Evolution, 4th Edition

gENETIC dRIfT: EvolUTIoN AT RANdoM 179 The relative contributions that adaptation and drift make to the differences among specie ...

180 CHAPTER 7 Crossing an adaptive valley by drift Adaptation can sometimes result when drift acts against selection. Many chrom ...

gENETIC dRIfT: EvolUTIoN AT RANdoM 181 kinds of beneficial mutations occur repeatedly, and in those cases one of the copies will ...

182 CHAPTER 7 in a shark. But while the protein’s similarity does not correlate with the habitat that these animals live in, it ...

gENETIC dRIfT: EvolUTIoN AT RANdoM 183 accumulate differences more rapidly than will sites that experi- ence strong purifying se ...

184 CHAPTER 7 saw that a selective sweep leaves a region of depressed polymorphism in the region of chromosome near where a sele ...

gENETIC dRIfT: EvolUTIoN AT RANdoM 185 possibility is that most nonsynonymous mutations are deleterious and are removed by purif ...

186 CHAPTER 7 The dN/dS ratio is a conservative test for adaptation: it often has a value less than 1 even when positive selecti ...

gENETIC dRIfT: EvolUTIoN AT RANdoM 187 Futuyma Kirkpatrick Evolution, 4e Sinauer Associates Troutt Visual Services Evolution4e_0 ...

■■Random genetic drift is the change in allele fre- quencies caused by chance events of survival, re- production, and meiosis. U ...

in the 1960s. Since then, a much-tempered version has become woven into the fabric of modern evolutionary biology. Accounts of o ...

08_EVOL4E_CH08.indd 190 3/23/17 9:12 AM ...

Clover is said to confer good luck to any person who finds a four-leafed plant, but for herbivores coming across a clover is les ...

192 CHAPTER 8 Patterns in Space The geographic variation of cyanide-producing clover is an example of a cline, which is a smooth ...

EVoluTioN iN SPACE 193 Other clines are very much shorter. A grass called the common bent (Agrostis capillaris) grows on and aro ...

194 CHAPTER 8 and other marine animals that are sedentary as adults have planktonic larvae that are dispersed hundreds or even t ...

EVoluTioN iN SPACE 195 where pm is the allele’s frequency in the migrants and p is its frequency in the focal population before ...

196 CHAPTER 8 results in an excess of homozygotes and a deficit of heterozygotes (see Chapter 7). A second effect of migration i ...

EVoluTioN iN SPACE 197 colonized different parts of Earth. A similar pattern can also result from a balance between gene flow an ...

198 CHAPTER 8 populations is strong evidence for adaptation, and opens the possibility of finding the genes that are involved [1 ...