GRADUATE STUDIES BULLETIN
ANNOUNCEMENT
Master’s Thesis Defense
Isolation and Characterization of Nuclear Microsatellite
Markers in the
Sailfin Molly, Poecilia latipinna
by
The purpose of this study was to develop high-resolution genetic markers for the parentage assignments in the sailfin molly, Poecilia latipinna, and test their utility with laboratory-raised individuals. Males of P. latipinna exhibit alternative mating behaviours, courtship display and gonopodial thrusting. Assessment of genetic mating success (fertilizing success) of the alternative behavioural morphs is necessary to evaluate the fitness of each morph and to understand the mechanisms controlling their frequencies.
“Microsatellites” are DNA sequences consisting of a sequence motif of one to six bases, that are tandemly repeated. The inherent instability of microsatellites makes them exceptionally useful for evolutionary and genetic studies. (CA)n dinucleotide microsatellites were isolated using PCR-based enrichment, followed by affinity capture with Vectrex avidin D. Primers were designed from the sequences of positive clones of the (CA)n repeat-enriched library. Genotypes of 34 parents and 144 offspring were obtained using fluorescence-labeled PCR, followed by laser-scanning detection.
Four (CA)n microsatellite loci were found to be highly polymorphic with observed heterozygosities ranging from 0.873 to 1.000. Total probability of identity for all loci was 3.22 ´ 10-9. Total exclusion probabilities were 0.9975 and 0.9997 for the first and the second parent, respectively. Mendelian inheritance of alleles was confirmed at all 4 loci. There were no linkage disequilibria among 4 microsatellite loci. Thus, a panel of 4 microsatellite markers described in this study offers high exclusionary power in parentage assignment.
Date: November 27, 2001 Department: Biological Sciences
Time: 1:30 pm Major Professor: Dr. Joel C. Trexler
Place: University Park, OE 134