Introgression through rare hybridisation: A genetic study of a hybrid zone between red and sika deer (genus Cervus), in Argyll, Scotland Journal Article


Author(s): Goodman, Simon J; Barton, Nicholas H; Swanson, Graeme M; Abernethy, Kate; Pemberton, Josephine M
Article Title: Introgression through rare hybridisation: A genetic study of a hybrid zone between red and sika deer (genus Cervus), in Argyll, Scotland
Affiliation
Abstract: In this article we describe the structure of a hybrid zone in Argyll, Scotland, between native red deer (Cervus elaphus) and introduced Japanese sika deer (Cervus nippon), on the basis of a genetic analysis using 11 microsatellite markers and mitochondrial DNA. In contrast to the findings of a previous study of the same population, we conclude that the deer fall into two distinct genetic classes, corresponding to either a sika-like or red- like phenotype. Introgression is rare at any one locus, but where the taxa overlap up to 40% of deer carry apparently introgressed alleles. While most putative hybrids are heterozygous at only one locus, there are rare multiple heterozygotes, reflecting significant linkage disequilibrium within both sika- and red-like populations. The rate of backcrossing into the sika population is estimated as H = 0.002 per generation and into red, H = 0.001 per generation. On the basis of historical evidence that red deer entered Kintyre only recently, a diffusion model evaluated by maximum likelihood shows that sika have increased at ~9.2% yr-1 from low frequency and disperse at a rate of ~3.7 km yr-1. Introgression into the red-like population is greater in the south, while introgression into sika varies little along the transect. For both sika- and red-like populations, the degree of introgression is 30-40% of that predicted from the rates of current hybridization inferred from linkage disequilibria; however, in neither case is this statistically significant evidence for selection against introgression.
Keywords: Animals; Alleles; Hybridization, Genetic; Scotland; Heterozygote; Microsatellite Repeats; Models, Statistical; Linkage Disequilibrium; Deer; DNA, Mitochondrial
Journal Title: Genetics
Volume: 152
Issue 1
ISSN: 0016-6731
Publisher: Genetics Society of America  
Date Published: 1999-05-01
Start Page: 355
End Page: 371
Open access: no