J. Andrew DeWoody

Ongoing projects in the DeWoody lab

Immunogenetics

David Bos has characterized major histocompatibility complex (MHC) variation in a population of wild tiger salamanders.  Despite MHC monomorphism in immunodeficient axolotls (Laurens et al. 2001, Eur J Immun 31:506), David has found plenty of variation in congeneric tiger salamanders (Bos and DeWoody 2005; Bos et al. 2008).  Evidence from a variety of other vertebrates suggests this variation may be maintained by both natural selection and sexual selection (i.e., mate choice).

Sexual Selection

Natural selection

Because they produce tens of thousands of eggs, fish are well suited for studies of survivorship.  Sara Turner raised Atlantic salmon and compared levels of relatedness in the parents to determine if outbred parents have greater hatching success than closely related parents. She also looked at MHC variability and its potential impact on survivorship in light of evidence that Atlantic salmon choose their mates on the basis of MHC genotype (Landry et al. 2001, Proc Roy Soc 268:1279).  Sara found that MHC zygosity influences susceptibility to bacterial kidney disease.

SNPs

We are interested in using microsatellites and/or single nucleotide polymorphisms (SNPs) to estimate relatedness in natural populations. On a per locus basis, microsatellites are much more informative than SNPs (most of which are biallelic). However, DNA chip technology provides a means whereby hundreds or thousands of SNPs can be assayed at once. Can the impressive number of available SNP loci overcome the inherent lack of polymorphism exhibited by these markers? No, say simulations by postdoc Jeff Glaubitz! (Glaubitz, Rhodes, and DeWoody 2003 Molecular Ecology 12:1039)

Monitoring

Wildlife biologists now use of noninvasively-collected hair samples as a source of DNA for population monitoring (e.g., enumeration), but Jamie Rudnick used feathers to monitor population turnover in the Eastern Imperial Eagle.  She documented that eagles are genetically monogamous, highly philopatric, and choose mates without regard to relatedness (Rudnick et al. 2005) and that hundreds of juveniles roost together.

Genomics

Sex-determining genes in mammals and birds have served as useful markers for conservation biologists who wish to determine sex from fecal samples or shed feathers.  However, such assays are difficult or impossible in most fishes because of the plasticity of sex-determining genes in this diverse group.  For lake sturgeon, PCR-based sex tests would be valuable because these fish are endangered, do not reach sexual maturity until 15-20 years of age, are sexually monomorphic, and are not reproductively active every year.  So far, efforts to isolate sex-determining genes in sturgeon have been unsuccessful, but we are now using cDNA analyses of lake sturgeon gonads in an effort to isolate the master gene.