scholarly journals Mitochondrial DNA Phylogenetics of Black Rhinoceros in Kenya in relation to Southern Africa Population

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Elijah K. Githui ◽  
David N. Thuo ◽  
Joshua O. Amimo ◽  
Nyamu M. Njagi ◽  
Maryanne M. Gitari
Keyword(s):  
Genetic Diversity ◽  
Mitochondrial Dna ◽  
Southern Africa ◽  
Wildlife Conservation ◽  
Eastern Africa ◽  
Black Rhinoceros ◽  
Low Genetic Diversity ◽  
History Of ◽  
Eastern And Southern Africa ◽  
Game Hunting

Black rhinoceros (Diceros bicornis) are highly endangered due to poaching and other anthropological reasons and their protection to rebound the numbers and genetic improvement are necessary remedial measures defined by Rhino International Union of Conservation for the Nature Red List (IUCN). In Kenya black rhino numbers declined from approximately 20,000 in the 1970s to fewer than 400 in 1982. Wildlife conservation managers effected strategies to manage/breed the remaining rhinoceros populations in Eastern and Southern Africa within regional sanctuaries. This study analyzes the genetic variability of these remnant rhinoceros using Mitochondrial DNA (mtDNA). Majority of the rhinoceros in both Kenyan and Southern Africa group are monophyletic clusters with insignificant genetic variations while some lineages are underrepresented. The Eastern Africa rhinoceros forms a distinct clade from the Sothern Africa counterpart while Tanzania population has admixtures. Tajima-D test showed that these two populations are under different selection pressure possibly due to different history of adverse anthropologic activities. Similarly, the Southern Africa rhinoceros have low genetic diversity compared to the Eastern African population due to extended periods of game hunting during Africa colonization. This study suggests that managed translocations of individual rhinoceros across the separated fragments can be applied to improve their genetic diversity.

Low genetic diversity and inbreeding depression in Queensland Koalas

1993 ◽  
Vol 20 (2) ◽  
pp. 177 ◽  
Author(s):  
JMW Wilmer ◽  
A Melzer ◽  
F Carrick ◽  
C Moritz
Keyword(s):  
Genetic Diversity ◽  
Mitochondrial Dna ◽  
Inbreeding Depression ◽  
Natural Populations ◽  
Small Population ◽  
Phascolarctos Cinereus ◽  
Low Genetic Diversity ◽  
History Of ◽  
Biased Sex Ratio ◽  
Two Populations

The amount of genetic variation in two natural populations of Queensland koalas (Phascolarctos cinereus adustus) was assessed by analysis of mitochondrial DNA. Levels and any adverse effects of inbreeding (inbreeding depression) were estimated from the pedigree of a well-characterised captive colony. Genetic diversity of mitochondrial DNA was found to be exceedingly low both within and between the two populations, but the variation detected was found to be strongly structured geographically. Inbreeding levels in the captive colony were moderate to high yet the only apparent evidence of inbreeding depression was a male-biased sex ratio. There was no evidence for decreased juvenile survivorship or growth rate with inbreeding. Because of the limited data it would be premature to conclude that koalas are relatively resistant to the effects of inbreeding. However, we suggest the hypothesis that koalas have a history of small population size, resulting in reduced susceptibility to inbreeding depression.

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.

Structure and History of African Elephant Populations: I. Eastern and Southern Africa

1994 ◽  
Vol 85 (2) ◽  
pp. 100-104 ◽  
Author(s):  
N. Georgiadis ◽  
L. Bischof ◽  
A. Templeton ◽  
J. Patton ◽  
W. Karesh ◽  
...  
Keyword(s):  
Southern Africa ◽  
African Elephant ◽  
History Of ◽  
Eastern And Southern Africa

No Evidence of Low Genetic Diversity Despite High Levels of Inbreeding and Poor Genetic Connectivity Among Tetrastigma loheri (Vitaceae) Populations in Remaining Forest Areas in Cebu, Philippines

2021 ◽  
Vol 46 (4) ◽  
pp. 951-961
Author(s):  
Jasper John A. Obico ◽  
Hemres Alburo ◽  
Julie F. Barcelona ◽  
Marie Hale ◽  
Lisa Paguntalan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Habitat Fragmentation ◽  
Tropical Forests ◽  
Forest Cover ◽  
Genetic Connectivity ◽  
Philippine Island ◽  
Low Genetic Diversity ◽  
History Of ◽  
Gap Data ◽  
The Impact

Abstract— Little is known about the effects of habitat fragmentation on the patterns of genetic diversity and genetic connectivity of species in the remaining tropical forests of Southeast Asia. This is particularly evident in Cebu, a Philippine island that has a long history of deforestation and has lost nearly all of its forest cover. To begin filling this gap, data from 13 microsatellite loci developed for Tetrastigma loheri (Vitaceae), a common vine species in Philippine forests, were used to study patterns of genetic diversity and genetic connectivity for the four largest of the remaining forest areas in Cebu. Evidence of relatively high levels of inbreeding was found in all four areas, despite no evidence of low genetic diversity. The four areas are genetically differentiated, suggesting low genetic connectivity. The presence of inbreeding and low genetic connectivity in a commonly encountered species such as T. loheri in Cebu suggests that the impact of habitat fragmentation is likely greater on rare plant species with more restricted distributions in Cebu. Conservation recommendations for the remaining forest areas in Cebu include the establishment of steppingstone corridors between nearby areas to improve the movement of pollinators and seed dispersers among them.

Comparative mitochondrial phylogeography of two legless lizards (Pygopodidae) from Queensland’s fragmented woodlands

2020 ◽  
Vol 66 (3-4) ◽  
pp. 142-150
Author(s):  
Jessica Worthington Wilmer ◽  
Andrew P. Amey ◽  
Carmel McDougall ◽  
Melanie Venz ◽  
Stephen Peck ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Evolutionary History ◽  
The West ◽  
European Settlement ◽  
Low Genetic Diversity ◽  
Eastern Australia ◽  
Wide Range ◽  
History Of ◽  
Open Forests ◽  
Fossorial Species

Sclerophyll woodlands and open forests once covered vast areas of eastern Australia, but have been greatly fragmented and reduced in extent since European settlement. The biogeographic and evolutionary history of the biota of eastern Australia’s woodlands also remains poorly known, especially when compared to rainforests to the east, or the arid biome to the west. Here we present an analysis of patterns of mitochondrial genetic diversity in two species of Pygopodid geckos with distributions centred on the Brigalow Belt Bioregion of eastern Queensland. One moderately large and semi-arboreal species, Paradelma orientalis, shows low genetic diversity and no clear geographic structuring across its wide range. In contrast a small and semi-fossorial species, Delma torquata, consists of two moderately divergent clades, one from the ranges and upland of coastal areas of south-east Queensland, and other centred in upland areas further inland. These data point to varying histories of geneflow and refugial persistance in eastern Australia’s vast but now fragmented open woodlands. The Carnarvon Ranges of central Queensland are also highlighted as a zone of persistence for cool and/or wet-adapted taxa, however the evolutionary history and divergence of most outlying populations in these mountains remains unstudied.

scholarly journals Evolution of the U.S. Biological Select AgentRathayibacter toxicus

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Edward W. Davis ◽  
Javier F. Tabima ◽  
Alexandra J. Weisberg ◽  
Lucas Dantas Lopes ◽  
Michele S. Wiseman ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Adaptive Immune System ◽  
The United States ◽  
Genomic Diversity ◽  
Data Set ◽  
Important Species ◽  
Content Type ◽  
Low Genetic Diversity ◽  
History Of ◽  
Short Palindromic Repeat

ABSTRACTRathayibacter toxicusis a species of Gram-positive, corynetoxin-producing bacteria that causes annual ryegrass toxicity, a disease often fatal to grazing animals. A phylogenomic approach was employed to model the evolution ofR. toxicusto explain the low genetic diversity observed among isolates collected during a 30-year period of sampling in three regions of Australia, gain insight into the taxonomy ofRathayibacter, and provide a framework for studying these bacteria. Analyses of a data set of more than 100 sequencedRathayibactergenomes indicated thatRathayibacterforms nine species-level groups.R. toxicusis the most genetically distant, and evidence suggested that this species experienced a dramatic event in its evolution. Its genome is significantly reduced in size but is colinear to those of sister species. Moreover,R. toxicushas low intergroup genomic diversity and almost no intragroup genomic diversity between ecologically separated isolates.R. toxicusis the only species of the genus that encodes a clustered regularly interspaced short palindromic repeat (CRISPR) locus and that is known to host a bacteriophage parasite. The spacers, which represent a chronological history of infections, were characterized for information on past events. We propose a three-stage process that emphasizes the importance of the bacteriophage and CRISPR in the genome reduction and low genetic diversity of theR. toxicusspecies.IMPORTANCERathayibacter toxicusis a toxin-producing species found in Australia and is often fatal to grazing animals. The threat of introduction of the species into the United States led to its inclusion in the Federal Select Agent Program, which makesR. toxicusa highly regulated species. This work provides novel insights into the evolution ofR. toxicus.R. toxicusis the only species in the genus to have acquired a CRISPR adaptive immune system to protect against bacteriophages. Results suggest that coexistence with the bacteriophage NCPPB3778 led to the massive shrinkage of theR. toxicusgenome, species divergence, and the maintenance of low genetic diversity in extant bacterial groups. This work contributes to an understanding of the evolution and ecology of an agriculturally important species of bacteria.

scholarly journals Genetic structure and sex-biased gene flow in the history of southern African populations

2017 ◽  
Author(s):  
Vladimir Bajić ◽  
Chiara Barbieri ◽  
Alexander Hübner ◽  
Tom Güldemann ◽  
Christfried Naumann ◽  
...  
Keyword(s):  
Gene Flow ◽  
Y Chromosome ◽  
Southern Africa ◽  
Social Dynamics ◽  
Population History ◽  
Eastern Africa ◽  
The Social ◽  
African Populations ◽  
History Of ◽  
Over Time

ABSTRACTObjectivesWe investigated the genetic history of southern African populations with a special focus on their paternal history. We reexamined previous claims that the Y-chromosome haplogroup E1b1b was brought to southern Africa by pastoralists from eastern Africa, and investigated patterns of sex-biased gene flow in southern Africa.Material and MethodsWe analyzed previously published complete mtDNA genome sequences and ~900 kb of NRY sequences from 23 populations from Namibia, Botswana and Zambia, as well as haplogroup frequencies from a large sample of southern African populations and 23 newly genotyped Y-linked STR loci for samples assigned to haplogroup E1b1b.ResultsOur results support an eastern African origin for Y-chromosome haplogroup E1b1b; however, its current distribution in southern Africa is not strongly associated with pastoralism, suggesting a more complex origin for pastoralism in this region. We confirm that the Bantu expansion had a notable genetic impact in southern Africa, and that in this region it was probably a rapid, male-dominated expansion. Furthermore, we find a significant increase in the intensity of sex-biased gene flow from north to south, which may reflect changes in the social dynamics between Khoisan and Bantu groups over time.ConclusionsOur study shows that the population history of southern Africa has been very complex, with different immigrating groups mixing to different degrees with the autochthonous populations. The Bantu expansion led to heavily sex-biased admixture as a result of interactions between Khoisan females and Bantu males, with a geographic gradient which may reflect changes in the social dynamics between Khoisan and Bantu groups over time.

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