F13 lecture 23

Ucscedubio175lectures11molecularevolu1onpdf

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: d to the rates of replacement subs1tu1on, silent subs1tu1ons usually outnumber replacement subs1tu1ons by 5- 10 fold => most evolu1on involves silent subs1tu1ons - likely by gene1c dri] => Kimura proposed the NEUTRAL THEORY OF MOLECULAR EVOLUTION in 1968 "the survival of the luckiest" Recall the classical versus balanced controversy in evolu1onary biology •  Classical view predicted liple varia1on in nature, balance view predicted abundant varia1on in nature –  Molecular analysis showed that there was abundant molecular varia1on •  This does not necessarily confirm the Balance view –  Because most of this varia1on may be neutral (which was not proposed by the Balance school) •  Balance school thought varia1on (heterozygosity) was adap1ve hpp://bio.classes.ucsc.edu/bio175/Lectures/11_Molecular_Evolu1on.pdf Star1ng in the 1960s •  We know that allozyme polymorphism is abundant –  What caused Kimura to propose that this varia1on is mostly neutral? •  1. “segrega1on load” – if it wasn’t neutral, it would have to be selected against – i.e. lots of deaths •  E.g. human sickle cell locus hpp://bio.classes.ucsc.edu/bio175/Lectures/11_Molecular_Evolu1on.pdf The molecular clock hpp://bio.classes.ucsc.edu/bio175/Lectures/11_Molecular_Evolu1on.pdf hpp://bio.class...
View Full Document

This document was uploaded on 02/27/2014.

Ask a homework question - tutors are online