Low Genetic Variability in the Highly Endangered Mediterranean Monk Seal

Abstract

Genetic variability is an important component in the ability of populations to adapt in the face of environmental change. Here we report the first description of nuclear genetic variability in the only remaining sizable colony of the Mediterranean monk seal (Monachus monachus), located at Cap Blanc (Western Sahara, Mauritania), whose estimated size during the study period (1994-May 1997) was about 320 individuals. We tested 42 microsatellite loci isolated from five pinniped species in a sample of 52 pups. Three loci failed to give any product, and of the remaining 39, only 15 were polymorphic, with a maximum of 3 alleles detected. Three loci appeared to be X-linked. No departures from Hardy-Weinberg equilibrium were detected and no genetic structure was found between the two nursing caves currently occupied by the seals. Several analytical methods show that, as a consequence of a severe bottleneck, the population has suffered a decrease in genetic variability over the last few centuries.

Genome-Wide Loss of Diversity in the Critically Endangered Hawaiian Monk Seal

“…An effective population size of N e = 2 for ten generations (Figure 3) is required to achieve the present level of heterozygosity (assuming an initial heterozygosity of H O = 0.75 [41]). While this is not impossible, it seems unlikely given that 1,500 seal skins were reportedly landed by the Gambia in 1859 [31] and that by 1958, 900 non-pup individuals were observed during NWHI beach counts [42].…”

“…We assumed an average initial heterozygosity (H 0 = 0.75) following similar analyses of the Mediterranean monk seal [41]. We plotted the loss of heterozygosity over a range of time (0-200 generations).…”

Anthropogenics: Human Influence on Global and Genetic Homogenization of Parasite Populations

“…This is contrary to the phocids of the Arctic-Boreal region, whose population size has decreased dramatically from human activity, i.e., hunting, bycatch, viral diseases, etc. (Hauksson, 2002;Barron et al, 2003;Pastor et al, 2004;Di Guardo et al, 2005;Andersen et al, 2006;Harding et al, 2007). Similarly, Antarctic fish species belonging to the Channictiydae, Bathydraconidae, and Nototheniidae, and that function as intermediate hosts for these nematodes, have not been subject to the population reduction from overfishing that has occurred in host fish species, i.e., Gadus morhua, in the Boreal region found infected by the Arctic members of the C. osculatum complex (Cook et al, 1997;Masood, 1997).…”

Creation Nerves of the Lumbar and Sacral Plexus in California Sea Lions (Zalophus Californianus) and Northern Elephant Seals (Mirounga Angustirostris)/Formiranje Nerava Iz Lumbalnog I Sakralnog Pleksusa Kod Kalifornijskog Morskog Lava (Zalophus Californianus) I Severnomorskog Slona (Mirounga Angustirostris)

“…Some authors [22][23][24][25][26][27] chose to investigate the behavior, growth and development of different species of sea lions. Genetic variability was also investigated in some pinnipedia [26,[28][29][30]. However, very few authors investigated their nervous system, especially the peripheral nervous system.…”