Variations and genetic relationships of the garter-snakes

Ruthven, Alexander G.

doi:10.5479/si.03629236.61.1

Cited by 26 publications

(25 citation statements)

References 2 publications

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“…Garter snake diversity is highest in Mexico, with 18 of 30 or so described species occurring there. In our study, the biogeographic pattern displayed by the species in both the elegans group and the sirtalis group supports a modified version of Ruthven's (1908) hypothesis (Fig. 7).…”

Section: Biogeography Of the Garter Snakes And Water Snakessupporting

confidence: 70%

Molecular Systematics and Evolution of Regina and the Thamnophiine Snakes

Alfaro

Arnold

2001

Molecular Phylogenetics and Evolution

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Section: Biogeography Of the Garter Snakes And Water Snakessupporting

confidence: 70%

Molecular Systematics and Evolution of Regina and the Thamnophiine Snakes

Alfaro

Arnold

2001

Molecular Phylogenetics and Evolution

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“…Conversely, others have demonstrated that overlap in both dorsal and labial scale counts is occasionally observed between these two species (Ruthven 1908;Logier 1939;Smith 1945Smith , 1949Planck and Planck 1977), leading one to question the significance of reduced scale counts in Luther Marsh and whether they are within the normal extremes for T. butleri and not evidence for hybridization or the presence of T. brachystoma in Canada. Nonetheless, based on the central geographic position of Luther Marsh relative to the known range of both T. brachystoma and T. butleri and the presence of hybridization between T. butleri and other Thamnophis elsewhere (T. radix: Fitzpatrick et al 2008), it seems plausible to hypothesize a hybrid zone at Luther Marsh.…”

Section: Introductionmentioning

confidence: 90%

Population genetic structure of the endangered Butler’s Gartersnake (Thamnophis butleri): does the Short-headed Gartersnake (Thamnophis brachystoma) exist in Canada?

et al. 2013

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Understanding population genetic structure is fundamental to conservation of endangered species. It is particularly important when working with species that are morphologically conserved because strong genetic divisions could represent cryptic species. Butler's Gartersnake (Thamnophis butleri (Cope, 1889)) is an endangered species in Canada, having a fragmented distribution and being restricted to southwestern Ontario. Furthermore, it is difficult to distinguish morphologically from a closely related species, the Short-headed Gartersnake (Thamnophis brachystoma (Cope, 1892)). We use mitochondrial DNA (mtDNA) and seven microsatellite DNA loci to evaluate the genetic structure of Canadian T. butleri populations and to test for the presence of T. brachystoma in one of these populations. All individuals had the same mtDNA haplotype, and there was no evidence of multiple, syntopic genetic clusters, thereby rejecting the hypothesis that T. butleri and T. brachystoma co-exist in Canada. Two different model-based assignment tests using microsatellite DNA data suggest that there are four to five genetically distinct clusters of T. butleri (F ST from 0.12 to 0.20). We provide the first population genetic study of T. butleri in Canada and refute the presence of T. brachystoma. Our results may provide guidance on recovery strategies for this species and identify areas to target fine-scale genetic analyses.Résumé : La compréhension de la structure génétique des populations est un aspect fondamental de la conservation des espèces en voie de disparition et est particulièrement importante dans le cas d'espèces morphologiquement conservées étant donné que de fortes divisions génétiques peuvent représenter des espèces cryptiques. La couleuvre à petite tête (Thamnophis butleri (Cope, 1889)) est une espèce en voie de disparition au Canada, son répartition, limitée au sud-ouest de l'Ontario, étant fragmentée. Il est en outre difficile de la distinguer, sur une base morphologique, de Thamnophis brachystoma (Cope, 1892), une espèce étroitement apparentée. Nous utilisons l'ADN mitochondrial (ADNmt) et sept microsatellites d'ADN pour évaluer la structure génétique des populations canadiennes de T. butleri et vérifier la présence de T. brachystoma dans une de ces populations. Tous les individus présentent le même haplotype d'ADNmt, et rien n'indique la présence de multiples groupements génétiques syntopiques, ce qui invalide l'hypothèse de la coexistence de T. butleri et T. brachystoma au Canada. Deux tests d'affectation différents reposant sur des modèles et faisant appel aux données de microsatellites d'ADN laissent croire à la présence de quatre à cinq groupements génétiques distincts de T. butleri (F ST de 0,12 à 0,20). Nous présentons la première étude de la génétique des populations de la couleuvre à petite tête au Canada et démontrons l'absence de la couleuvre T. brachystoma. Nos résultats pourraient servir à orienter les stratégies visant le rétablissement de T. butleri et à cerner les zones à cibler des analyses génétiques fines....

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“…1): number of ventral scales (VENT); number of subcaudal scales (SUB); total number of infralabial (ILAB), supralabial (SLAB), postocular (POST) scales on the left and right sides; number of dorsal scale rows at midbody (MID). Conventions for making these counts are described by Ruthven (1908), Dowling (1951), and Peters (1964). The counts were made on stillborn animals (approximately 5% of the neonate sample), even when deformed, as well as on liveborn neonates.…”

Section: Samples Of Snakes and Scoring Of Traitsmentioning

confidence: 99%

HIERARCHICAL COMPARISON OF GENETIC VARIANCE‐COVARIANCE MATRICES. II COASTAL‐INLAND DIVERGENCE IN THE GARTER SNAKE, THAMNOPHIS ELEGANS

Arnold

Phillips

1999

Evolution

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Abstract.-The time-scale for the evolution of additive genetic variance-covariance matrices (G-matrices) is a crucial issue in evolutionary biology. If the evolution of G-matrices is slow enough, we can use standard multivariate equations to model drift and selection response on evolutionary time scales. We compared the G-matrices for meristic traits in two populations of garter snakes (Thamnophis elegans) with an apparent separation time of 2 million years. Despite considerable divergence in the meristic traits, foraging habits, and diet, these populations show conservation of structure in their G-matrices. Using Flury's hierarchial approach to matrix comparisons, we found that the populations have retained the principal components (eigenvectors) of their G-matrices, but their eigenvalues have diverged. In contrast, we were unable to reject the hypothesis of equal environmental matrices (E-matrices) for these populations. We propose that a conserved pattern of multivariate stabilizing selection may have contributed to conservation of G-and E-matrix structure during the divergence of these populations.

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Variations and genetic relationships of the garter-snakes

Cited by 26 publications

References 2 publications

Molecular Systematics and Evolution of Regina and the Thamnophiine Snakes

Molecular Systematics and Evolution of Regina and the Thamnophiine Snakes

Population genetic structure of the endangered Butler’s Gartersnake (Thamnophis butleri): does the Short-headed Gartersnake (Thamnophis brachystoma) exist in Canada?

HIERARCHICAL COMPARISON OF GENETIC VARIANCE‐COVARIANCE MATRICES. II COASTAL‐INLAND DIVERGENCE IN THE GARTER SNAKE, THAMNOPHIS ELEGANS

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