February_4_2013_NKW

Thus higher mutaon rate per unit me compared to

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: g. 10.14 8 Human ­chimp sequence divergence on different chromosomes largely non ­coding 1.  What is the best explana&on for the differences on X and Y compared to autosomes? 2. How would you es&mate the muta&on rate from this average 1.2% divergence between chimps and humans? NEUTRAL THEORY American Journal of Human Gene&cs 2002 70:1490 Human ­chimp sequence divergence on different chromosomes (sequence is largely non ­coding) 1.  What is the best explana7on for the differences in divergence on X and Y compared to autosomes?  ­Y chromosome occurs only in males, undergoes more replica&ons per unit &me. Thus, higher muta&on rate per unit &me compared to autosomes Male ­Biased Muta&on  ­X chromosome occurs mostly in females (2/3 are in females in any one genera&on), thus has a lower average muta&on rate per unit &me compared to autosomes. 2. How would you es7mate the muta7on rate from this average 1.2% divergence between chimps and humans? since K=u (subs&tu&on rate=muta&on rate) divergence &me=6 million years (fossils) human 0.012 changes/site/12 million years 6 Mya 1.2% 0.001 subs&&ons/site/million year chimp NEUTRAL THEORY 9 Divergence time •  This equation might allow you to calculate divergence times between lineages more quickly : •  t = D/2u •  t = time since divergence from a common ancestor •  D = number of base pair differences between two sequences. •  u = neutral mutation rate Human ­chimp sequence divergence on different chromosomes (sequence is largely non ­coding) 2. How would you es7mate the divergence 7me given a 0.001 subs7tu7ons/site/ million years and average 1.2% divergence between...
View Full Document

Ask a homework question - tutors are online