Publications : Larissa M. Williams

Signatures of selection in natural populations adapted to chronic pollution
Williams LM, Oleksiak MF (2008) Signatures of selection in natural populations adapted to chronic pollution. BMC Evolutionary Biology, 8:282.

This 2008 paper was the first genomic scan (using AFLPs) of multiple natural populations of the teleost fish, Fundulus heteroclitus, which are adapted to pollution.

SNP identification and verification using high-throughput methods in a non-model genus
Williams LM, Ma X, Boyko AR, Bustamante CD, Oleksiak MF. (2010) SNP identification and verification using high-throughput methods in a non-model genus. BMC Genetics, 11:32.

By targeting SNPs contained in both coding and non-coding areas of the genome, we were able to identify genetic differences and characterize genome-wide patterns of variation among individuals, populations and species. We investigated the utility of 454 sequencing and MassARRAY genotyping for population genetics in natural populations of the teleost, Fundulus heteroclitus as well as closely related Fundulus species (F. grandis, F. majalis and F. similis).

Functional genomics of physiological plasticity and local adaptation in killifish: an emerging model in environmental genomics
Whitehead A, Galvez Z., Zhang S., Williams LM, Oleksiak MF. (2010) Functional genomics of physiological plasticity and local adaptation in killifish: an emerging model in environmental genomics. Journal of Heredity. doi:10.1093/jhered/esq077

We show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes.

Selectively important SNPs identified in natural populations
Williams LM, Oleksiak MF. 2011. Selectively important SNPs identified in natural populations. Molecular Biology and Evolution. doi: 10.1093/molbev/msr00

Three statistical tests were used to identify SNPs under selection in multiple natural populations of Fundulus heteroclitus adapted to pollution.

Evolutionary and functional analyses of cytochrome P4501A promoter polymorphisms in natural populations
In this 2011 paper, we document extensive genetic variation in the cytochrome P450 1A promoter between Fundulus heteroclitus populations from two clean sites and one polluted site. Despite this extensive variation among populations and lack of fixed differences between populations, individuals from a polluted environment have significantly enhanced promoter activity (which is opposite what was expected since CYP1A transcription and enzyme activity is refratory to induction). These data demonstrate that intraspecific variation, which provides the raw material for natural selection to act on, can occur while maintaining promoter function.

Last updated: February 3, 2011