{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Bio 321 F13 lecture 6 for post

gene1c varia1on required for evolu1onary

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: selection variation within populations very low high variation between populations much greater than intrapopulation variation not much greater than intra-population variation selection usually “purifying” “balancing” (heterozygot e advantage) h)p://www.monmsci.net/~kbaldwin/popgen.03.notes.pdf BIO 367/BEE 567 lecture 1 19 Evidence favors the Balance view (somewhat) •  Lewon1n, Hubby 1966 –  Used protein electrophoresis to show that varia1on at the molecular level was common •  Late 60s, 70s, 80s “era of allozymes” –  30- 50% of loci studied have at least 2 electrophore1c variant in popula1ons –  Individuals heterozygous at 6- 12% of loci •  (Drosophila) •  (human/mammals est. 6- 7%, based on amino acid sequences) BIO 367/BEE 567 lecture 1 20 Allozymes •  =“allele” + “enzyme” •  Polymorphisms involving charge differences in metabolic enzymes •  Recognized using electrophore1c separa1on of protein extracts •  Lewon1n and Hubby (1966) –  Examined 18 gene loci from 6 popula1ons (Drosophila pseudoobscura) –  Only 11 of 18 loci were monomorphic (no allozyme varia1on) –  39% of loci turned out to be polymorphic for allozymes –  Led to predic1on: 8- 15% of all loci will be polymorphic (typically expressed as likelihood an individual will be BIO367/BEE 567 Lab 1 Fall 05 heterozygous) http://en2.wikipedia.org/wiki/Amino_acid BIO367/BEE 567 Lab 1 Fall 05 =usually negative at physiological pH =usually positive at physiological pH =sometimes positive at physiological pH Amino acid subs1tu1ons •  May or may not change the charge of the protein •  If net charge of protein is altered, electrophore1c mobility will change –  Basis of “allozymes” (allele + enzyme) BIO367/BEE 567 Lab 1 Fall 05 BIO367/BEE 567 Lab 1 Fall 05 Allozymes are co-dominant markers =can tell all three genotypes previous slide only had homozygotes (inbred lines) example of heterozygotes for an allozome locus http://www.zoology.siu.edu/ heist/images/ SunfishAllozyme.jpg Taq polymerase Restric+on Endonucleases •  Also called “restric1on enzymes” •  Originally from bacteria –  What might bacteria use them for? •  Enzymes that cut DNA at precise sequences –  Dozens of different enzymes with different “cut sites” Restric1on cut sites are ouen variable: RFLPs = Restric1on Fragment Length Polymorphisms •  pre- PCR •  PCR- era isolate genomic DNA from in...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online