A Test of an Allopatric Speciation Model for Congeneric Amphipods in an Isolated Aquatic Ecosystem

Thomas, Elizabeth; Blinn, W.; Keim, Paul

doi:10.2307/1467270

Cited by 18 publications

(17 citation statements)

References 25 publications

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“…The private allele found in population TB with a low frequency might be an exotic gene resulting from pollen contamination. In addition, according to Thomas et al (1994), disjunctive habitats, and population isolation in general, affect a species' ability to survive and disperse. In the circumstances, the isolated habitats of P. asperata have played an important role in preventing sufficient gene flow, which has consequently lead to a considerable genetic heterogeneity among populations (Wright 1943, Kimura and Weiss 1964, Endler 1977.…”

Section: Discussionmentioning

confidence: 99%

Allozyme variation in natural populations of Picea asperata

Luo¹,

Wang²,

Korpelainen³

et al. 2005

Silva Fenn.

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A survey of allozymic alleles and genetic diversity was conducted for ten natural populations of Picea asperata Mast. originating from the mountains of Southwest China. A total of twenty-seven alleles at seventeen loci were observed. Ten of the loci were found monomorphic. Our results showed that the populations sampled were characterized by low genetic diversity (mean He = 0.096) and a low level of inbreeding (mean Fis = 0.005). The UPGMA tree of genetic relationships indicated that there was significant differentiation among populations. The coefficient of genetic differentiation among populations, based on Fst, equaled 0.311. Such extensive inter-populational differentiation detected in P. asperata could have resulted from allele frequency divergence among populations, particularly, in one population. Introgression from another species, variation in environmental conditions, and differing selection pressures could be some of the factors attributing to significant differences among populations. In addition, our results showed that the geographic and genetic distances were not correlated in the populations of P. asperata. Based on the genetic information obtained, we concluded that monitoring appropriate genetic markers may be an effective means of identifying potential genetic changes occurring during forest tree evolution.

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Section: Discussionmentioning

confidence: 99%

Allozyme variation in natural populations of Picea asperata

Luo¹,

Wang²,

Korpelainen³

et al. 2005

Silva Fenn.

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“…In spite of apparent morphological consistency, high levels of genetic divergence and variation have been found in passively dispersed invertebrate groups (Hebert 1974;Burton 1986;Boileau and Hebert 1991;Jackson and Resh 1992;Thomas et al 1994Thomas et al , 1997. This includes examples of invertebrates with significantly differentiated populations in adjacent habitats despite the small geographic distances separating them (Hebert 1974;Hedgecock 1986;Boileau and Hebert 1991;Jackson and Resh 1992;Qian and Davies 1996).…”

Section: Introductionmentioning

confidence: 99%

Cryptic radiation in erpobdellid leeches in xeric landscapes: a molecular analysis of population differentiation

Govedich¹,

Blinn²,

Hevly³

et al. 1999

Can. J. Zool.

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Despite apparent long-term geographic isolation, many invertebrates demonstrate little apparent morphological differentiation. To examine underlying genetic differentiation, eight erpobdellid leech populations from widely dispersed northern Arizona aquatic ecosystems were examined by means of amplified fragment length polymorphism genetic markers. These populations were primarily Erpobdella punctata, though two populations, Motobdella montezuma and Motobdella sedonensis, have been described as novel taxa. Data from 137 polymorphic loci were used to estimate genetic heterogeneity (θ), migration rates (Nm), and genetic similarities (Dice's method) among these populations. Analysis of molecular variance and cluster analysis (unweighted pair-group method) were used to show population structure and to partition the genetic variance. Our analysis indicates that northern Arizona leech populations are genetically isolated (θ = 0.72, Nm = 0.09), with significant (p < 0.01) differentiation among populations. In addition, no relationship was found between genetic and geographic distances (r = 0.19, p = 0.22), which is consistent with long-term isolation even when populations are in close proximity. The large amount of genetic differentiation reveals levels of diversity and complexity not apparent from morphological comparisons alone and suggests that erpobdellid leeches in the arid landscape of the southwestern U.S.A. are in fact evolving independently from one another.Résumé : En dépit de leur isolement géographique probable de longue date, plusieurs invertébrés semblent avoir subi peu de différenciation morphologique. Pour évaluer la différenciation génétique sous-jacente, nous avons procédé à l'examen de marqueurs génétiques AFLP (polymorphisme de longueur de fragments amplifiés) chez huit populations de sangsues erpobdellidées provenant d'écosystèmes aquatiques dispersés du nord de l'Arizona. Ces populations sont surtout des Erpobdella punctata, mais deux d'entre elles, Motobdella montezuma et Motobdella sedonensis, ont été décrites comme de nouveaux taxons. Les données sur 137 locus polymorphes ont servi à estimer l'hétérogénéité génétique (θ), les taux de migration (Nm) et les similarités génétiques (Dice) chez ces populations. L'analyse de la variance moléculaire et une analyse des groupements par la méthode des mesures pairées non pondérées ont servi à examiner la structure de la population et à fractionner la variance génétique. Les résultats indiquent que les populations de sangsues du nord de l'Arizona sont isolées génétiquement (θ = 0,72, Nm = 0,09) et diffèrent significativement (p < 0,01) les unes des autres. De plus, aucune relation n'a été trouvée entre les distances génétique et géographique (r = 0,19, p = 0,22), ce qui prévaut normalement lorsque l'isolement génétique remonte à loin dans le temps, même chez des populations qui vivent près les unes des autres. L'importance de la différenciation génétique reflète un degré de diversité et de complexité qui ne se manifeste pas lors des comparaisons strictement...

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“…Other molecular and biochemical studies published in J-NABS have focused on intraspecific variation, in particular population structure (Sweeney et al 1986, Gibbs et al 1998, Geenen et al 2000, Elderkin and Klerks 2001, Monaghan et al 2002, Yam and Dudgeon 2005, Pauls et al 2009), phylogeography (Kauwe et al 2004), speciation (Thomas et al 1994), cryptic species (Duan et al 2000), genetic differentiation and its implication in conservation (Geenen et al 2000), and larval differentiation (MacDonald and Harkrider 1999). A few population genetic studies have formulated hypotheses that have been acknowledged and tested widely in the literature.…”

Section: Biochemical and Molecular Systematicsmentioning

confidence: 99%