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Evidence of positive selection on a homeotic mutant of Aquilegia coerulea

Award Period: 

Tuesday, May 1, 2018 to Tuesday, April 30, 2019

Award Amount: 

$9 387

Agency Name: 

American Genetic Association

Award Number: 

SB180174

PI First Name: 

Zachary

PI last name: 

Cabin

Co-PI: 

Scott Hodges

Area/s of Research: 

Abstract: 

Naturally occurring homeotic mutants offer a rare chance to study how a radical morphological shift affects fitness. Aquilegia coerulea var. daileyae is a homeotic mutant where the petals, with long spurs and a nectar reward, have been changed into a second set of sepals. While, this change would appear to be deleterious due to the loss of the nectar reward, I have found that the mutant consistently has a fitness advantage in a polymorphic population and has reached fixation in two other populations. Previous work identified a candidate locus (AP3-3) and I have found that non-functional alleles are perfectly associated with the mutant phenotype. I have found elevated LD at these mutant alleles indicating strong natural selection. I propose to re-sequence individuals from the polymorphic and fixed populations (and nearby wild-type populations) to determine (a) how far the elevated LD extends around AP3-3 and (b) if other regions in the genome also experience similar selection. With this information, I will be able to demonstrate current ecological selective pressure with and molecular signatures of selection favoring a radical homeotic mutant.