The Response to Past Climate Perturbations Explains Extremely Low Genetic Diversity in the Genome of an Abundant Ice-Age Remnant, the Alpine Marmot

2018 ◽  
Author(s):  
Toni I. Gossmann​ ◽  
Achchuthan Shanmugasundram​ ◽  
Stefan Börno ◽  
Ludovic Duvaux ◽  
Christophe Lemaire​ ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ice Age ◽  
Past Climate ◽  
Low Genetic Diversity ◽  
Alpine Marmot

scholarly journals Ice-Age Climate Adaptations Trap the Alpine Marmot in a State of Low Genetic Diversity

2019 ◽  
Vol 29 (10) ◽  
pp. 1712-1720.e7 ◽  
Author(s):  
Toni I. Gossmann ◽  
Achchuthan Shanmugasundram ◽  
Stefan Börno ◽  
Ludovic Duvaux ◽  
Christophe Lemaire ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ice Age ◽  
Low Genetic Diversity ◽  
Alpine Marmot

scholarly journals Genetic footprint of population fragmentation and contemporary collapse in a freshwater cetacean

2016 ◽  
Author(s):  
Minmin Chen ◽  
Michael C. Fontaine ◽  
Yacine Ben Chehida ◽  
Jinsong Zheng ◽  
Frédéric Labbe ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Habitat Degradation ◽  
Field Studies ◽  
Mitigation Strategies ◽  
Ice Age ◽  
Background Information ◽  
Conservation Strategies ◽  
Low Genetic Diversity ◽  
Neophocaena Asiaeorientalis Asiaeorientalis

AbstractUnderstanding demographic trends and patterns of gene flow in an endangered species is crucial for devising conservation strategies. Here, we examined the extent of population structure and recent evolution of the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis). By analysing genetic variation at the mitochondrial and nuclear microsatellite loci for 148 individuals, we identified three populations along the Yangtze River, each one connected to a group of admixed ancestry. Each population displayed extremely low genetic diversity, consistent with extremely small effective size (≤92 individuals). Habitat degradation and distribution gaps correlated with highly asymmetric gene-flow that was inefficient in maintaining connectivity between populations. Genetic inferences of historical demography revealed that the populations in the Yangtze descended from a small number of founders colonizing the river from the sea during the last Ice Age. The colonization was followed by a rapid population split during the last millennium predating the Chinese Modern Economy Development. However, genetic diversity showed a clear footprint of population contraction over the last 50 years leaving only ~2% of the pre-collapsed size, consistent with the population collapses reported from field studies. This genetic perspective provides background information for devising mitigation strategies to prevent this species from extinction.

Season of birth interacts with measures of inbreeding in multiplex schizophrenia pedigrees: evidence from genetic isolates in Daghestan

Open Medicine ◽  
2006 ◽  
Vol 1 (4) ◽  
pp. 392-398
Author(s):  
Kazima Bulayeva ◽  
John McGrath
Keyword(s):  
Genetic Diversity ◽  
Family History ◽  
Age Of Onset ◽  
Population Genetic Study ◽  
Season Of Birth ◽  
High Genetic Diversity ◽  
Low Genetic Diversity ◽  
High Prevalence ◽  
History Of ◽  
Genetic Isolates

AbstractWhile the season-of-birth effect is one of the most consistent epidemiological features of schizophrenia, there is a lack of consistency with respect to the interaction between season of birth and family history of schizophrenia. Apart from family history, measures related to consanguinity can be used as proxy markers of genomic heterogeneity. Thus, these measures may provide an alternate, indirect index of genetic susceptibility. We had the opportunity to explore the interaction between season of birth and measure of consanguinity in well-described genetic isolates in Daghestan, some of which are known for their relatively high prevalence of schizophrenia. Our previous population-genetic study showed Daghestan has an extremely high genetic diversity between the ethnic populations and a low genetic diversity within them. The isolates selected for this study include some with more than 200 and some with less than 100 generations of demographical history since their founding. Based on pedigrees of multiply-affected families, we found that among individuals with schizophrenia, the measure of consanguinity was significantly higher in the parents of those born in winter/spring compared to those born in summer/autumn. Furthermore, compared to summer/autumn born, winter/spring born individuals with schizophrenia had an earlier age-of-onset, and more prominent auditory hallucinations. Our results suggest that the offspring of consanguineous marriages, and thus those with reduced allelic heterogeneity, may be more susceptible to the environmental factor(s) underpinning the season-of-the effect in schizophrenia.

scholarly journals Low genetic diversity in the endangered Taxus yunnanensis following a population bottleneck, a low effective population size and increased inbreeding

2016 ◽  
Vol 65 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Y. C. Miao ◽  
Z. J. Zhang ◽  
J. R. Su
Keyword(s):  
Genetic Diversity ◽  
Habitat Fragmentation ◽  
Population Size ◽  
Effective Population Size ◽  
Spatial Genetic Structure ◽  
Population Bottleneck ◽  
Effective Population ◽  
Taxus Yunnanensis ◽  
Low Genetic Diversity ◽  
Two Populations

Abstract Taxus yunnanensis, which is an endangered tree that is considered valuable because it contains the effective natural anticancer metabolite taxol and heteropolysaccharides, has long suffered from severe habitat fragmentation. In this study, the levels of genetic diversity in two populations of 136 individuals were analyzed based on eleven polymorphic microsatellite loci. Our results suggested that these two populations were characterized by low genetic diversity (NE = 2.303/2.557; HO = 0.168/0.142; HE = 0.453/0.517), a population bottleneck, a low effective population size (Ne = 7/9), a high level of inbreeding (FIS = 0.596/0.702), and a weak, but significant spatial genetic structure (Sp = 0.001, b = −0.001*). Habitat fragmentation, seed shadow overlap and limited seed and pollen dispersal and potential selfing may have contributed to the observed gene tic structure. The results of the present study will enable development of practical conservation measures to effectively conserve the valuable genetic resources of this endangered plant.

scholarly journals Low Genetic Diversity in the Rare Madeiran Endemic Armeria maderensis (Plumbaginaceae)

2009 ◽  
Vol 44 (1) ◽  
pp. 65-81 ◽  
Author(s):  
Rosalía Piñeiro ◽  
Javier Fuertes Aguilar ◽  
Miguel Menezes de Sequeira ◽  
Gonzalo Nieto Feliner
Keyword(s):  
Genetic Diversity ◽  
Low Genetic Diversity

Marked differences in genetic diversity and differentiation between the centre and edge of the geographical range of Megaleranthis saniculifolia (Ranunculaceae), a Korean endemic species

2012 ◽  
Vol 60 (7) ◽  
pp. 582
Author(s):  
Ji Hee Jeong ◽  
Zin-Suh Kim
Keyword(s):  
Genetic Diversity ◽  
Peripheral Region ◽  
Issr Markers ◽  
Ex Situ ◽  
Allele Frequency Distribution ◽  
Low Genetic Diversity ◽  
Long Time ◽  
Megaleranthis Saniculifolia ◽  
Degree Of Differentiation ◽  
Substantial Degree

The amount and distribution of genetic diversity within and between Megaleranthis saniculifolia Ohwi populations were compared between the central and peripheral regions of the species distribution. Allozyme and ISSR markers were used for genetic analysis of six populations from the central region (DY) and five populations from the peripheral region (MJ). Genetic diversity was substantially higher in the DY region than in the MJ region. Relatively uniform homozygote excess at many loci in most populations indicated that M. saniculifolia was influenced by a substantial degree of inbreeding in both regions. The degree of differentiation between populations was remarkably higher in the MJ region than in the DY region. Cluster analysis showed a trend towards separation between regions, although populations in the MJ region exhibited a slightly different trend according to the markers. We conclude that genetic drift has been affecting the populations in the MJ region for a long time, on the basis of their low genetic diversity, high differentiation, U-shaped allele-frequency distribution, and fixation of alleles towards opposing frequencies (1 or 0) among populations. In contrast, the DY region maintained relatively stable populations, although evidence of a recent bottleneck was found in one population. Along with some practical measures for genetic conservation, we present an optimal sample size for ex situ conservation to secure as many common alleles as possible.

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