Spring/Summer 2001

Current Research: Reproductive Success of Male White-tailed Deer

Dr. Steve DeMaris and Randy DeYoung of the Forest and Wildlife Research Center at Mississippi State University are researching the effect of population sex ratio on relative genetic influence of individual bucks on selected study areas in Mississippi.

To accomplish this objective they first had to develop protocols for collecting and analyzing genetic samples that will enable us to determine paternity for individual deer.

They completed development of a 20-locus microsatellite marker panel for use in white-tailed deer in conjunction with researchers at Texas A&M University and the Samuel Roberts Noble Foundation. The panel is highly informative and will be useful for genetic exclusion and population structure research. The panel is currently being used to investigate microgeographic population structure in free-ranging white-tails on the Noble Foundation Wildlife Unit as well as their research. To date, they have typed a total of 1,025 deer from research pens (261 deer) and from the wild (764 deer).

They sampled 35 fawns produced in 3 separate single-sire research pens to evaluate the usefulness of our panel in paternity assignment. They combined all fawns into 1 file and analyzed for paternity as if it were 1 single-sire pen. They assigned paternity to 100% of the fawns with 99% confidence. Other pens were used to evaluate how age and social dominance affected breeding success of bucks. Each year 2-3 males and 6-12 females are randomly assigned to each pen. Social behavior is observed during the breeding season to estimate the male dominance hierarchy within each pen. Paternity results are then compared to the observed dominance hierarchy. Preliminary results from fawns born in 3 research pens during summer 1999 suggest that socially dominant males sired most offspring. They inferred a dominance shift between 2 males in 1 research pen by behavioral observation that was later borne out by parentage assignment.

They identified 9 study areas where we will have the greatest likelihood of obtaining an adequate sample of the breeding population to determine paternity in free-ranging deer. These study areas are: Ashbrook Island and Walker Brothers DMAP clubs, Juniper Creek Farms private club, Malmaison and Tallahala WMAs and Noxubee National Wildlife Refuge in Mississippi; the Noble Foundation Wildlife Unit in southeastern Oklahoma (Wildlife Unit sampling is part of ongoing research by K. L. Gee, Noble Foundation); and 2 10,000-acre areas on the King Ranch in southern Texas. Sex ratios on these areas range from balanced to 1 buck per 10 does.

They examined preliminary results (19-locus genotypes) for 219 deer from 8 populations in Mississippi, and 1 population each in the Florida panhandle, southeastern Oklahoma, and southern Texas. The results were used to estimate genetic similarity among white-tailed deer populations in Mississippi and compare them to presumed outcrossing groups (the Florida, Texas and Oklahoma populations) that are separated by greater geographic distance. The population statistics indicate that the panel will be useful for fine-scale genetic research and the similarity of values between populations suggests that the panel will be informative in most white-tailed deer populations throughout the southern United States.