Water Snakes in Lake Erie Water snakes (Nerodia sipedon) in Lake Erie come in two color phases:...
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Transcript of Water Snakes in Lake Erie Water snakes (Nerodia sipedon) in Lake Erie come in two color phases:...
Water Snakes in Lake Erie• Water snakes (Nerodia
sipedon) in Lake Erie come in two color phases: banded and unbanded
• This is a two allele system• Banded dominant to
unbanded• The mainland has really only
banded• The islands may have both
• King & Lawson, 1995
Lake Erie water snakes
• It was found that, when basking on islands, the unbanded snakes are more cryptic and thus remain hidden better.
• Why wouldn’t selection cause the unbanded pattern to go to fixation?
• Migration. Every year, banded snakes migrate from the mainland and introduce fresh banded alleles
• Therefore, migration offsets selection
Genetic Drift
Founder Effect• small founding populations have less allelic diversity
• Clegg, et al, 2002
Silvereye (Zosterops lateralis)
Silvereye colonization
• Clegg, et al, 2002
Founder Effect on Allelic Diversity of the Silvereye
Alleles Randomly Fixed
Average Heterogosity Decreases
Alleles Randomly fixed in the field
Collared Lizard (Crotaphytus collaris)
• Templeton, et al, 2002
Multilocus Genotyping of Collared Lizards in the Ozarks
Randomly Fixed Alleles in Isolated Collared Lizard Populations
The Vertebrate Mitochondrial Genetic Code
Alcohol Dehydrogenase (ADH) Gene Alignment in Drosophilia
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