Genetic analysis reveals population structure and recent migration within the highly fragmented range of the Cross River gorilla (Gorilla gorilla diehli)

Anthropology Department, City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA.
Molecular Ecology (Impact Factor: 6.49). 03/2007; 16(3):501-16. DOI: 10.1111/j.1365-294X.2006.03159.x
Source: PubMed


Recently developed methods of individual-based analysis of genetic data allow an unprecedented opportunity to understand the relationships among fragmented populations. By defining population structure and identifying migrant individuals, such analyses can provide a framework to aid in evaluating the threats posed by inbreeding and reduced genetic variability as a consequence of limited gene flow among fragments. Here we investigate population structure in the critically endangered Cross River gorilla (Gorilla gorilla diehli) by applying a suite of individual-based analyses to data obtained from between one-quarter and one-third of the estimated total population through the use of noninvasively collected DNA samples. The population structure inferred using data from 11 autosomal microsatellite loci was broadly consistent with geography and habitat fragmentation, but showed no simple isolation-by-distance effects. In contrast to previous field surveys, which suggested that all gorilla localities were isolated from one another, we infer low levels of gene flow and identify migrants between habitat fragments as well as individuals of admixed ancestry, suggesting persistent recent reproductive contact between many of the localities. These results are encouraging for the conservation of the Cross River gorilla population. Conservation efforts should strive to maintain connectivity between subpopulations that are still in migratory contact and attempt to restore connectivity where it has been lost.

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Available from: Linda Vigilant, Mar 23, 2015
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    • "The value of K that best explains the genetic partition of the data is given by its highest probability. When sampling social groups, the presence of highly related dyads of individuals in the sample may induce family-based structure that does not correspond to a true population (Anderson and Dunham, 2008; Bergl and Vigilant, 2007; Pritchard and Wen, 2004). This was the case of the P. b. temminckii population, for which the inclusion of related individuals in the dataset produced a strong family-based structure (Fig. A1). "
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    ABSTRACT: The ability of forest-dwelling species to adapt to changes in their habitat is being increasingly challenged by the rapid pace of human-induced forest degradation. Understanding the effect of such environmental changes on biodiversity requires comparative analyses across species living within the same habitats. We investigated the effect of forest exploitation on the genetic structure and demography of two sympatric arboreal primates showing differences in their socioecology: the Western black-and-white colobus (Colobus polykomos) and Temminck's red colobus (Procolobus badius temminckii). We conducted the study in a fragmented and human-impacted forest in Guinea Bissau. Using microsatellite data from six C. polykomos and eight P. b. temminckii social groups, we found that in C. polykomos the distribution of genetic diversity followed an isolation-by-distance pattern whereas for P. b. temminckii, the results suggested restriction in female dispersal. We detected a strong, recent bottleneck for both primates, which we inferred to have resulted from the anthropogenic exploitation of forest resources in the last centuries. The bottleneck signal was stronger for P. b. temminckii as a likely consequence of its larger estimated ancestral population size. Finally, we discussed the different analytical approaches used. Our results confirm that P. b. temminckii is more affected by habitat changes than C. polykomos, despite being phylogenetically close. Nonetheless, the low estimated effective population sizes and the known demographic changes indicate that both species are severely threatened by human forest exploitation, requiring urgent conservation action.
    Full-text · Article · Feb 2016 · Biological Conservation
    • "Genetic diversity is also an important factor for conservation status. Thus, analysis of the genetic structure of a population can provide information that is essential to the conservation of the population or species [Bergle & Vigilant, 2007]. Sex-biased dispersal patterns affect the population genetic structure [Eriksson et al., 2006; Langergraber et al., 2007]. "
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    No preview · Article · Jun 2015 · American Journal of Primatology
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    • "This can be particularly important when the focal species of the study occurs in sympatry with related taxa [13]. Analyses based on faecal DNA have been applied to a broad range of taxa to address questions from occupancy and food habits to abundances, species distribution, and habitat use [14] [15] [16] [17] [18] [19] [13]. "
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