Mitochondrial DNA and the phylogeography of Newfoundland black bears

1996 ◽  
Vol 74 (1) ◽  
pp. 192-196 ◽  
Author(s):  
David Paetkau ◽  
Curtis Strobeck

The degree of genetic differentiation separating Newfoundland black bears (Ursus americanus hamiltoni) from continental Canadian black bears (U. a. americanus and U. a. cinnamomum) was assessed using sequence data from part of the mitochondrial DNA molecule. All of the individuals from insular Newfoundland, New Brunswick, and Quebec, and most of the individuals from Alberta, had very closely related haplotypes. Haplotypes from Newfoundland animals were more similar to those in eastern Canada than the eastern Canadian lineages were to related lineages in Alberta black bears. Given the previous observation of reduced genetic diversity in Newfoundland black bears, this subspecies likely arose through rapid genetic drift associated with a founder effect during postglacial colonization of the island, and not through long periods of isolation in a glacial refugium.

2017 ◽  
Vol 95 (8) ◽  
pp. 527-537 ◽  
Author(s):  
James W. Patterson ◽  
Anna M. Duncan ◽  
Kelsey C. McIntyre ◽  
Vett K. Lloyd

Ixodes scapularis Say, 1821 (the black-legged tick) is becoming established in Canada. The northwards expansion of I. scapularis leads to contact between I. scapularis and Ixodes cookei Packard, 1869, a well-established tick species in Eastern Canada. Examination of I. cookei and I. scapularis collected from New Brunswick revealed ticks with ambiguous morphologies, with either a mixture or intermediate traits typical of I. scapularis and I. cookei, including in characteristics typically used as species identifiers. Genetic analysis to determine if these ticks represent hybrids revealed that four had I. cookei derived mitochondrial DNA but I. scapularis nuclear DNA. In one case, the nuclear sequence showed evidence of heterozygosity for I. scapularis and I. cookei sequences, whereas in the others, the nuclear DNA appeared to be entirely derived from I. scapularis. These data strongly suggest genetic hybridization between these two species. Ixodes cookei and hybrid ticks were readily collected from humans and companion animals and specimens infected with Borrelia burgdorferi Johnson et al., 1984, the causative agent of Lyme disease, were identified. These findings raise the issue of genetic introgression of I. scapularis genes into I. cookei and warrant reassessment of the capacity of I. cookei and I. cookei × I. scapularis hybrids to vector Borrelia infection.


2011 ◽  
Vol 89 (9) ◽  
pp. 831-839 ◽  
Author(s):  
H. Dawn Marshall ◽  
Edward S. Yaskowiak ◽  
Casidhe Dyke ◽  
Elizabeth A. Perry

We investigated population structure of black bears ( Ursus americanus hamiltoni Cameron, 1957) from insular Newfoundland using the microsatellite profiles of 12 loci from three broadly distributed areas (Northern, Baie Verte, and Bonavista peninsulas). Our goals were to revisit earlier findings of low heterozygosity in Newfoundland and increase knowledge of intraspecific variability in black bears, and make inferences about postglacial colonization and contemporary movements of island black bears. Ninety-three individuals (42 males) were identified among 543 hair samples: 21 from Bonavista, 25 from Northern Peninsula, and 47 from Baie Verte. Genetic diversity is relatively low (HE = 0.42) and decreases from northwest to southeast. Small but significant subpopulation differentiation revealed by F statistics is greatest between Northern and Baie Verte peninsulas; it is lower and comparable in the remaining pairwise comparisons. We hypothesize that postglacial colonization proceeded from the Northern Peninsula southeastward. Bears migrated from the Northern Peninsula to Baie Verte at some more distant time in the past, then diverged by genetic drift. More recently, migration occurred from these two populations to Bonavista, characterized by positive FIS indicative of admixture. Tests of biased dispersal and posterior probability of correct assignment to locality reveal contemporary movements of both males and females with historical dispersal attributable to males.


2009 ◽  
Vol 90 (5) ◽  
pp. 1075-1082 ◽  
Author(s):  
Ronald A. van den Bussche ◽  
Justin B. Lack ◽  
David P. Onorato ◽  
Lynne C. Gardner-Santana ◽  
Bonnie R. McKinney ◽  
...  

2006 ◽  
Vol 37 (3) ◽  
pp. 335-350 ◽  
Author(s):  
Jakob Damgaard

AbstractThis study addresses the phylogenetic relationships within and between two widespread Palaearctic pond skater species, Gerris costae and G. thoracicus, by including new DNA sequence data from the Central Asian G. sahlbergi, traditionally assigned as a close relative of G. costae. The results support the assignment of G. costae and G. thoracicus to two individual species groups that are not closely related, but also that G. sahlbergi is nested within G. costae (including subspecies costae, fieberi and poissoni) thus suggesting a new subspecific rank as G. c. sahlbergi. A broad geographical sampling of mitochondrial DNA from populations of G. thoracicus and G. costae (incl. G. c. sahlbergi) shows that the two species are strikingly similar in terms of genetic diversity and lack of geographical substructure, thus adding further evidence for the G. costae group comprising a single, widespread species.


2008 ◽  
Vol 363 (1508) ◽  
pp. 3427-3437 ◽  
Author(s):  
Renae C Pratt ◽  
Mary Morgan-Richards ◽  
Steve A Trewick

New Zealand taxa from the Orthopteran family Anostostomatidae have been shown to consist of three broad groups, Hemiandrus (ground weta), Anisoura/Motuweta (tusked weta) and Hemideina – Deinacrida (tree–giant weta). The family is also present in Australia and New Caledonia, the nearest large land masses to New Zealand. All genera are endemic to their respective countries except Hemiandrus that occurs in New Zealand and Australia. We used nuclear and mitochondrial DNA sequence data to study within genera and among species-level genetic diversity within New Zealand and to examine phylogenetic relationships of taxa in Australasia. We found the Anostostomatidae to be monophyletic within Ensifera, and justifiably distinguished from the Stenopelmatidae among which they were formerly placed. However, the New Zealand Anostostomatidae are not monophyletic with respect to Australian and New Caledonian species in our analyses. Two of the New Zealand groups have closer allies in Australia and one in New Caledonia. We carried out maximum-likelihood and Bayesian analyses to reveal several well supported subgroupings. Our analysis included the most extensive sampling to date of Hemiandrus species and indicate that Australian and New Zealand Hemiandrus are not monophyletic. We used molecular dating approaches to test the plausibility of alternative biogeographic hypotheses for the origin of the New Zealand anostostomatid fauna and found support for divergence of the main clades at, or shortly after, Gondwanan break-up, and dispersal across the Tasman much more recently.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 236-236
Author(s):  
Hee-Jong Roh ◽  
Chang-Yeon Cho ◽  
Seung-Chang Kim ◽  
Dong-Kyo Kim ◽  
Jinwook Lee ◽  
...  

Abstract Estimating the genetic diversity and origins is critical for the identification and conservation of valuable animal genetic resources. Mitochondrial DNA (mtDNA) polymorphisms have played a significant role in tracing the origin of specific breeds and the genetic diversity of domestic chicken and other livestock species due to their maternal inheritance, greater rate of substitution relative to unclear genes, and much lower rate of recombination. In this study, we analyzed the mtDNA D-loop region of 457 genomic DNA samples from 28 Asian chicken populations (Korea: 6, Laos: 4, Bangladesh: 3, Cambodia: 3, Indonesia: 3, Vietnam: 2, Kyrgyzstan: 1, Mongolia: 1, Nepal: 1, Sri Lanka: 1 and White Leghorn, Cornish, Rhode Island Red) from ten Asian countries to clarify their genetic diversity and phylogenetic relationships. In addition, 49 reference data (43: Oka et al data, 6: red jungle fowl) were used. We found 82 haplotypes defined by 81 variable sites. Overall haplotype and nucleotide diversity were 0.978±0.01 and 0.0018, respectively. Phylogenetic analyses revealed seven haplogroups (Type A-G). The most of Asian chickens were included in haplogroup A(44.9%), B(22.8%), C(19.3%). Haplogroup F did not belong to any Asian chicken populations (include only 2 reference data). Mongolia chickens were only clustered in haplogroup A and Indonesian chickens did only haplogroup C. About half of Kyrgyzstani chicken populations (43.4%) were clustered in haplogroup E. Vietnamese chicken populations belong to all haplogroup except F. In case of red jungle fowl, G.g.gallus and G.g.bankiva were clustered in haplogroup C. G.g.spadiceus was clusterd in haplogroup E or A. As a result, it was possible to identify the mtDNA diversity and origin of Asian chicken populations. In future studies, it is necessary to understand the origin of each haplogroup by adding more reference data and red jungle fowl sequence data.


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