An exceptional mode of mtDNA inheritance involving separate maternal and paternal transmission ro... more An exceptional mode of mtDNA inheritance involving separate maternal and paternal transmission routes has been reported recently in the mussel Mytilus edulis. This mode of inheritance provides an explanation for the high levels of heteroplasmy for two highly diverged genomes observed in males of this species. Here we provide evidence for a similar pattern of heteroplasmy in Atlantic and Mediterranean forms of the related mussel M. galloprovincialis. The results support the hypothesis that this mode of mtDNA inheritance has an ancient origin. In addition, the detection of some heteroplasmic females suggests preferential, rather than exclusive, transmission within male and female lines of descent. We also present evidence that the two highly diverged genomes display a parallel split between the Atlantic and Mediterranean forms, consistent with neutral evolution.
The study of spatial and temporal changes in hybrid zones offers important insights into speciati... more The study of spatial and temporal changes in hybrid zones offers important insights into speciation. Earlier studies on hybrid populations of the marine mussel speciesMytilus edulisandM. galloprovincialisin SW England provided evidence of admixture but were constrained by the limited number of molecular markers available. We use 57 highly ancestry-informative SNPs, most of which have been mapped genetically, to provide evidence of distinctive differences between highly admixed populations in SW England and asymmetrical introgression fromM. edulistoM. galloprovincialis. We combine the genetic study with analysis of phenotypic traits of potential ecological and adaptive significance. We demonstrate that hybrid individuals have brown mantle edges unlike the white or purple in the parental species, suggesting allelic or non-allelic genomic interactions. We report differences in gonad development stage between the species consistent with a prezygotic barrier between the species. By incor...
SUMMARYThe relationship between locus variability and genetic identity is analysed in pooled data... more SUMMARYThe relationship between locus variability and genetic identity is analysed in pooled data from a collection of Drosophila and vertebrate allozyme surveys. For vertebrates the analysis provides evidence that loci with high expected heterozygosity diverge at a faster rate than loci with low heterozygosity in comparisons involving pairs of populations and pairs of species. This relationship is not observed in comparisons of Drosophila species pairs.
Animal Blood Groups and Biochemical Genetics, 2009
Seventeen enzyme loci have been assayed for electrophoretically detectable variation in a populat... more Seventeen enzyme loci have been assayed for electrophoretically detectable variation in a population of the marine bivalve Scrobicularia plana. Mean heterozygosity is 0.120 +/- 0.033. In a comparison involving thirteen enzymes there is a significant correlation between heterozygosity in S. plana and Mytilus edulis and a suggestion of lower mean heterozygosity in S. plana. These findings are discussed in relation to current theories concerning the selective significance of protein variation.
... However, Lewis and Powell (1961) pointed out that sev-eral typically galloprovincialis charac... more ... However, Lewis and Powell (1961) pointed out that sev-eral typically galloprovincialis characters are widespread in British populations of M. edulis ... Using starch gel elec-trophoresis Ahmad andBeardmore (1976) found significant differences in allele fre-quency at three loci ...
Molecular Ecology.Editors Terry Burke, Ray Seidler and Harry Smith. Blackwell Scientific. 6/yr. U... more Molecular Ecology.Editors Terry Burke, Ray Seidler and Harry Smith. Blackwell Scientific. 6/yr. USA and Canada $335, Europe £205, elsewhere £225 (institutional); USA and Canada $61, Europe £35, elsewhere £41 (personal).
... Total 108 [78] 128 [188] 144 [114] structure of the Croyde population, a subject of previous ... more ... Total 108 [78] 128 [188] 144 [114] structure of the Croyde population, a subject of previous studies (eg Skibinski et al. ... University of Wales, Swansea Gardner, JPA, Skibinski, DOF (1988). Historical and size dependent genetic variation in hybrid mussel populations. ...
... D. 0. F. SKIBINSKI AND EE RODERICK School of Biological Sciences, University College of Swans... more ... D. 0. F. SKIBINSKI AND EE RODERICK School of Biological Sciences, University College of Swansea, Singleton Park, Swansea SA2 8PP Received 24 February 1989, accepted for publication 13 December 1989 ... Page 2. 352 D. 0. F. SKIBINSKI AND EE RODERICK ...
Allozyme variation in a population of the common mussel Mytilus edulis in Mumbles, South Wales, h... more Allozyme variation in a population of the common mussel Mytilus edulis in Mumbles, South Wales, has been studied by starch gel electrophoresis. On the basis of data obtained for 34 loci, we estimate the proportion of loci polymorphic to be 30%. Using only the 29 loci for which individual genotypes can be accurately typed, the average heterozygosity is estimated to be 9.5 +/- 3.6%. The calculated expected average heterozygosity based on Hardy-Weinberg expectations is identical with the observed value. Allele frequency data at six polymorphic loci are given for several other British populations. There is no significant geographic heterogeneity. The results are discussed in relation to genetic adaptive strategies and are shown to be inconsistent with the predictions of the neutral hypothesis.
Proteomic analysis was carried out on the Crab (upper-shore) and Wave (lower-shore) ecotypes of L... more Proteomic analysis was carried out on the Crab (upper-shore) and Wave (lower-shore) ecotypes of Littorina saxatilis from a hybrid zone at Silleiro Cape, Spain. Proteome profiles of individual snails were obtained. Protein expression in F1 hybrid snails bred in the laboratory and snails with intermediate shell phenotypes collected from the mid-shore were compared with Crab and Wave ecotypes using analytical approaches used to study dominance. Multivariate analysis over many protein spots showed that the F1 snails are distinct from both ecotypes but closer to the Wave ecotype. The intermediate snails are highly variable, some closer to the Crab and others to the Wave ecotype. Considered on a protein by protein basis, some proteins are significantly closer in expression to the Crab and others to the Wave ecotype for both F1 and intermediate snails. Furthermore, a significant majority of proteins were closer in expression to the Wave ecotype for the F1, consistent with the multivariate ...
An exceptional mode of mtDNA inheritance involving separate maternal and paternal transmission ro... more An exceptional mode of mtDNA inheritance involving separate maternal and paternal transmission routes has been reported recently in the mussel Mytilus edulis. This mode of inheritance provides an explanation for the high levels of heteroplasmy for two highly diverged genomes observed in males of this species. Here we provide evidence for a similar pattern of heteroplasmy in Atlantic and Mediterranean forms of the related mussel M. galloprovincialis. The results support the hypothesis that this mode of mtDNA inheritance has an ancient origin. In addition, the detection of some heteroplasmic females suggests preferential, rather than exclusive, transmission within male and female lines of descent. We also present evidence that the two highly diverged genomes display a parallel split between the Atlantic and Mediterranean forms, consistent with neutral evolution.
The study of spatial and temporal changes in hybrid zones offers important insights into speciati... more The study of spatial and temporal changes in hybrid zones offers important insights into speciation. Earlier studies on hybrid populations of the marine mussel speciesMytilus edulisandM. galloprovincialisin SW England provided evidence of admixture but were constrained by the limited number of molecular markers available. We use 57 highly ancestry-informative SNPs, most of which have been mapped genetically, to provide evidence of distinctive differences between highly admixed populations in SW England and asymmetrical introgression fromM. edulistoM. galloprovincialis. We combine the genetic study with analysis of phenotypic traits of potential ecological and adaptive significance. We demonstrate that hybrid individuals have brown mantle edges unlike the white or purple in the parental species, suggesting allelic or non-allelic genomic interactions. We report differences in gonad development stage between the species consistent with a prezygotic barrier between the species. By incor...
SUMMARYThe relationship between locus variability and genetic identity is analysed in pooled data... more SUMMARYThe relationship between locus variability and genetic identity is analysed in pooled data from a collection of Drosophila and vertebrate allozyme surveys. For vertebrates the analysis provides evidence that loci with high expected heterozygosity diverge at a faster rate than loci with low heterozygosity in comparisons involving pairs of populations and pairs of species. This relationship is not observed in comparisons of Drosophila species pairs.
Animal Blood Groups and Biochemical Genetics, 2009
Seventeen enzyme loci have been assayed for electrophoretically detectable variation in a populat... more Seventeen enzyme loci have been assayed for electrophoretically detectable variation in a population of the marine bivalve Scrobicularia plana. Mean heterozygosity is 0.120 +/- 0.033. In a comparison involving thirteen enzymes there is a significant correlation between heterozygosity in S. plana and Mytilus edulis and a suggestion of lower mean heterozygosity in S. plana. These findings are discussed in relation to current theories concerning the selective significance of protein variation.
... However, Lewis and Powell (1961) pointed out that sev-eral typically galloprovincialis charac... more ... However, Lewis and Powell (1961) pointed out that sev-eral typically galloprovincialis characters are widespread in British populations of M. edulis ... Using starch gel elec-trophoresis Ahmad andBeardmore (1976) found significant differences in allele fre-quency at three loci ...
Molecular Ecology.Editors Terry Burke, Ray Seidler and Harry Smith. Blackwell Scientific. 6/yr. U... more Molecular Ecology.Editors Terry Burke, Ray Seidler and Harry Smith. Blackwell Scientific. 6/yr. USA and Canada $335, Europe £205, elsewhere £225 (institutional); USA and Canada $61, Europe £35, elsewhere £41 (personal).
... Total 108 [78] 128 [188] 144 [114] structure of the Croyde population, a subject of previous ... more ... Total 108 [78] 128 [188] 144 [114] structure of the Croyde population, a subject of previous studies (eg Skibinski et al. ... University of Wales, Swansea Gardner, JPA, Skibinski, DOF (1988). Historical and size dependent genetic variation in hybrid mussel populations. ...
... D. 0. F. SKIBINSKI AND EE RODERICK School of Biological Sciences, University College of Swans... more ... D. 0. F. SKIBINSKI AND EE RODERICK School of Biological Sciences, University College of Swansea, Singleton Park, Swansea SA2 8PP Received 24 February 1989, accepted for publication 13 December 1989 ... Page 2. 352 D. 0. F. SKIBINSKI AND EE RODERICK ...
Allozyme variation in a population of the common mussel Mytilus edulis in Mumbles, South Wales, h... more Allozyme variation in a population of the common mussel Mytilus edulis in Mumbles, South Wales, has been studied by starch gel electrophoresis. On the basis of data obtained for 34 loci, we estimate the proportion of loci polymorphic to be 30%. Using only the 29 loci for which individual genotypes can be accurately typed, the average heterozygosity is estimated to be 9.5 +/- 3.6%. The calculated expected average heterozygosity based on Hardy-Weinberg expectations is identical with the observed value. Allele frequency data at six polymorphic loci are given for several other British populations. There is no significant geographic heterogeneity. The results are discussed in relation to genetic adaptive strategies and are shown to be inconsistent with the predictions of the neutral hypothesis.
Proteomic analysis was carried out on the Crab (upper-shore) and Wave (lower-shore) ecotypes of L... more Proteomic analysis was carried out on the Crab (upper-shore) and Wave (lower-shore) ecotypes of Littorina saxatilis from a hybrid zone at Silleiro Cape, Spain. Proteome profiles of individual snails were obtained. Protein expression in F1 hybrid snails bred in the laboratory and snails with intermediate shell phenotypes collected from the mid-shore were compared with Crab and Wave ecotypes using analytical approaches used to study dominance. Multivariate analysis over many protein spots showed that the F1 snails are distinct from both ecotypes but closer to the Wave ecotype. The intermediate snails are highly variable, some closer to the Crab and others to the Wave ecotype. Considered on a protein by protein basis, some proteins are significantly closer in expression to the Crab and others to the Wave ecotype for both F1 and intermediate snails. Furthermore, a significant majority of proteins were closer in expression to the Wave ecotype for the F1, consistent with the multivariate ...
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