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Severe Population Bottleneck (severe + population_bottleneck)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Reduced genetic variation in Norwegian Peregrine Falcons Falco peregrinus indicated by minisatellite DNA fingerprinting

IBIS, Issue 1 2002
Jan T. Lifjeld
The Scandinavian Peregrine Falcon Falco peregrinus population went through a severe population bottleneck during the second half of the twentieth century, and was almost extinct during the 1970s. This event may have reduced the amount of genetic variation in the population. With this background, a comparative study, using multilocus, minisatellite DNA fingerprinting, was carried out on broods of the Peregrine Falcon, the Merlin Falco columbarius and the Eurasian Hobby Falco subbuteo from south-east Norway. Band-sharing analysis of DNA fingerprints was used to test whether broods of Peregrine Falcons showed a greater between-nest similarity in their fingerprint profiles than did broods of the two congeneric species breeding in the same region, which have not undergone any recent population bottlenecks. The results show that broods of Peregrine Falcons were significantly more similar to each other genetically than were broods of either Merlins or Eurasian Hobbies. Furthermore, there was a positive correlation between the similarity in minisatellite DNA and the similarity in a set of 11 microsatellite loci analysed for a subset of the Peregrine Falcon samples. The correlation supports the assumption that minisatellite fingerprints provide a reliable indicator of overall genetic similarity, i.e. relatedness, between breeding pairs in the population. Hence we can conclude that broods of Peregrine Falcons were genetically more related to each other than were broods of the other two species. The high similarity in minisatellite DNA between broods indicates a loss of genetic variation in the Peregrine Falcon population caused by the bottleneck, but this explanation can only be verified through a comparative genetic study of individuals sampled before and after the bottleneck event. [source]

Phylogeography of lions (Panthera leo ssp.) reveals three distinct taxa and a late Pleistocene reduction in genetic diversity

MOLECULAR ECOLOGY, Issue 8 2009
ROSS BARNETT
Abstract Lions were the most widespread carnivores in the late Pleistocene, ranging from southern Africa to the southern USA, but little is known about the evolutionary relationships among these Pleistocene populations or the dynamics that led to their extinction. Using ancient DNA techniques, we obtained mitochondrial sequences from 52 individuals sampled across the present and former range of lions. Phylogenetic analysis revealed three distinct clusters: (i) modern lions, Panthera leo; (ii) extinct Pleistocene cave lions, which formed a homogeneous population extending from Europe across Beringia (Siberia, Alaska and western Canada); and (iii) extinct American lions, which formed a separate population south of the Pleistocene ice sheets. The American lion appears to have become genetically isolated around 340 000 years ago, despite the apparent lack of significant barriers to gene flow with Beringian populations through much of the late Pleistocene. We found potential evidence of a severe population bottleneck in the cave lion during the previous interstadial, sometime after 48 000 years, adding to evidence from bison, mammoths, horses and brown bears that megafaunal populations underwent major genetic alterations throughout the last interstadial, potentially presaging the processes involved in the subsequent end-Pleistocene mass extinctions. [source]

Phylogeography and conservation genetics of Eld's deer (Cervus eldi)

MOLECULAR ECOLOGY, Issue 1 2003
Christopher N. Balakrishnan
Abstract Eld's deer (Cervus eldi) is a highly endangered cervid, distributed historically throughout much of South Asia and Indochina. We analysed variation in the mitochondrial DNA (mtDNA) control region for representatives of all three Eld's deer subspecies to gain a better understanding of the genetic population structure and evolutionary history of this species. A phylogeny of mtDNA haplotypes indicates that the critically endangered and ecologically divergent C. eldi eldi is related more closely to C. e. thamin than to C. e. siamensis, a result that is consistent with biogeographic considerations. The results also suggest a strong degree of phylogeographic structure both between subspecies and among populations within subspecies, suggesting that dispersal of individuals between populations has been very limited historically. Haplotype diversity was relatively high for two of the three subspecies (thamin and siamensis), indicating that recent population declines have not yet substantially eroded genetic diversity. In contrast, we found no haplotype variation within C. eldi eldi or the Hainan Island population of C. eldi siamensis, two populations which are known to have suffered severe population bottlenecks. We also compared levels of haplotype and nucleotide diversity in an unmanaged captive population, a managed captive population and a relatively healthy wild population. Diversity indices were higher in the latter two, suggesting the efficacy of well-designed breeding programmes for maintaining genetic diversity in captivity. Based on significant genetic differentiation among Eld's deer subspecies, we recommend the continued management of this species in three distinct evolutionarily significant units (ESUs). Where possible, it may be advisable to translocate individuals between isolated populations within a subspecies to maintain levels of genetic variation in remaining Eld's deer populations. [source]

Decreased immunocompetence in a severely bottlenecked population of an endemic New Zealand bird

ANIMAL CONSERVATION, Issue 1 2007
K. A. Hale
Abstract Inbreeding resulting from severe population bottlenecks may impair an individual's immune system and render it more susceptible to disease. Although a reduced immune response could threaten the survival of highly endangered species, few studies have assessed the effect of population bottlenecks on immunocompetence. We compared the counts of leucocytes and external, blood and gastrointestinal parasite loads in two populations of the endemic New Zealand robin Petroica australis to assess the immunocompetence of birds in a severely bottlenecked population relative to its more genetically diverse source population. Despite similar parasite loads in both populations, robins in the severely bottlenecked population showed lower counts of both total leucocyte and total lymphocyte numbers. When the immune system was experimentally challenged using the phytohaemagglutinin skin test, robins in the severely bottlenecked population exhibited a significantly lower immune response than the source population, suggesting that birds passing through a severe bottleneck have a compromised immunocompetence. Our results confirm that severe bottlenecks reduce the immune response of birds and highlight the need to avoid severe bottlenecks in the recovery programmes of endangered species. [source]