Genetics


Genetic, conservation and behavior

Solomon Chak & Jacob Myers

One goal of conservation biology is to prevent the loss of biodiversity. Lost of genetic diversity or variation would reduce the evolvability and hence the survival potential of the species. Genetic techniques provide a way to examine and compare the genetic diversity between populations of a species.

Genetic techniques are also handy for certain behavioral ques-tions like parentage analysis, mating system and dispersal. Currently, microsatellite DNA is most widely used in this purpose. Moreover, experimental crosses can give insight to the heritability of specific behavioral trait, and reflect its adaptive significant.

Here are a few references related to using genetics in conservation and behavioral studies:

  • Chapman DD, Prodohl PA, Gelsleichter J et al. 2004. Predominance of Genetic monogamy by females in a hammerhead shark, Sphyrna tiburo:implications for shark conservation" Demian D. Molecular Ecology Febuary 2004 13:1965-1974

In this paper the researchers conducted a genetic test to the population of Bonnethead sharks off the west coast of Florida. Bonnethead sharks ( Sphyrna tiburo) are the smallest species of hammerhead sharks and are able to store sperm up to five months. This led researchers to hypothesize that the bonnethead would exhibit multiple paternity that is exhibited in Leopard and Nurse sharks. The genetic tests involved sacrificing 22 pregnant females to attain there litters. Then four loci were analyzed for parental alleles. If more then two parental alleles were found in the litter that indicated that there were multiple sires to the litter. After analyzing the results, the results showed that 18 of the 22 litters showed evidence of only one sire. This is in stark contrast to most other fishes which exhibit promiscuity except for those with highly specialized reproductive systems. This result also shows that one cannot necessarily tell what a mating system is just by observation alone, since Bonnetheads are socially promiscuous. For conservation, this has significant meaning in the over fishing of sharks. With these sharks being genetically monogamous, the over fishing will reduce genetic diversity significantly.

 

  • Ashley MC. 2004. Population Genetics of Feral Horses: Implications of Behavioral Isolation. Journal of Mammology. 85:611-61.

In this paper, the researchers examined several loci to see if the population of wild feral horses located in the Herd Managment Area (HMA) of Garfield flats were divided into two sub-populations. The horses come in contact only once a year over winter when foaling is the lowest. This reduces gene flow among the horses and divides them into two sub-populations. They analyzed the alleles by first observing the behavior of the horses and then collecting blood samples to analyze the alleles. The results showed that there was a significant differentiation among allele frequencies between Garfield Flats and Garfield Hills, the two sub-populations. This seems to indicate that the population is divided into two sub-populations. This has significance to the conservation and behavior, the separation of these two sub-populations was due to behavioral migration. To conservation this is important to other endangered or threatened animals in a similar situation, and to keep tabs on the genetic diversity of the species in question.

 

  • Anthony LL, Blumstein DT. 2000. Integrating behaviour into wildlife conservation: the multiple ways that behaviour can reduce N e. Biological Conservation 95:303-315.

Effective population size affects the variability of a population. This article discussed many behavior that can reduce Ne. Examples are mating system, dispersal, reproductive suppression, infanticide, migration. It links behavior, genetic and conservation together.

 

  • Storz JF, Bhat HR, Kunz TH. 2001. Genetic consequences of polygyny and social structure in an Indian fruit bat, Cynopterus sphinx II. Variance in male mating success and effective population size. Evolution 55:1224-1232.

In this article, researchers tested the hypothesis that polygynous mating causes significant reduced Ne. The hypothesis was not supported since overlapping of generations has reduced the effect of polygynous mating. They made use of two approaches to find the number of mating males using microsatellite genotypes: 1) direct matching of offspring and adult males’ genotypes (mother already known) and 2) using frequency of half-siblings in the offspring only.

 

  • Storfer A. 1996. Quantitative genetics: a promising approach for the assessment of genetic variation in endangered species. TREE 11:343-348.

This article compared using single locus allozymes, single locus DNA marker and multi-loci quantitative genetics to assess genetic variation. Although it did not include multiple DNA loci in the discussion, it has a great discussion of the pros and cons of using quantitative traits to test genetic variation, especially in the conservation context.

 
Figure courtesy of http://asicoaquaticmarkers.com/anatomyJ1.jpg

 

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