Dataset Information

Microsatellite and mitochondrial DNA homogeneity among phenotypically diverse crossbill taxa in the UK.

ABSTRACT: Genetic differentiation within and between the three morphologically divergent crossbill species extant in the UK was assessed by comparison of allele frequencies at five unlinked microsatellite loci and DNA sequence variation across the mitochondrial control region. No significant differences in microsatellite allele frequency were found either between different populations of the same species or between the crossbill species themselves. A similar lack of genetic divergence was apparent from the mitochondrial sequence data. We resolved 33 different haplotypes, separated by low levels of sequence divergence (0-0.15%). Levels of divergence within and between species were not significantly different. Haplotypes formed a polyphyletic phylogeny, indicating that the crossbill species do not form genetically separate clades. Discordance between neutral DNA polymorphisms and adaptive morphological variation is discussed in relation to defining the systematic relationship between crossbill forms. If adaptive differences have arisen without a concomitant divergence in neutral DNA then attempting to define crossbill types from microsatellite and mitochondrial DNA without recourse to ecology and behaviour may be misleading.

SUBMITTER: Piertney SB

PROVIDER: S-EPMC1088771 | biostudies-other | 2001 Jul

REPOSITORIES: biostudies-other

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Microsatellite and mitochondrial DNA homogeneity among phenotypically diverse crossbill taxa in the UK.

Piertney S B SB Summers R R Marquiss M M

Proceedings. Biological sciences 20010701 1475

Genetic differentiation within and between the three morphologically divergent crossbill species extant in the UK was assessed by comparison of allele frequencies at five unlinked microsatellite loci and DNA sequence variation across the mitochondrial control region. No significant differences in microsatellite allele frequency were found either between different populations of the same species or between the crossbill species themselves. A similar lack of genetic divergence was apparent from th ...[more]

PMID: 11454296

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Project description:BackgroundSaccharina japonica (Areschoug) Lane, Mayes, Druehl et Saunders is an economically important and highly morphologically variable brown alga inhabiting the northwest Pacific marine waters. On the basis of nuclear (ITS), plastid (rbcLS) and mitochondrial (COI) DNA sequence data, we have analyzed the genetic composition of typical Saccharina japonica (TYP) and its two common morphological varieties, known as the "longipes" (LON) and "shallow-water" (SHA) forms seeking to clarify their taxonomical status and to evaluate the possibility of cryptic species within S. japonica.ResultsThe data show that the TYP and LON forms are very similar genetically in spite of drastic differences in morphology, life history traits, and ecological preferences. Both, however, are genetically quite different from the SHA form. The two Saccharina lineages are distinguished by 109 fixed single nucleotide differences as well as by seven fixed length polymorphisms (based on a 4,286 bp concatenated dataset that includes three gene regions). The GenBank database reveals a close affinity of the TYP and LON forms to S. japonica and the SHA form to S. cichorioides. The three gene markers used in the present work have different sensitivity for the algal species identification. COI gene was the most discriminant gene marker. However, we have detected instances of interspecific COI recombination reflecting putative historical hybridization events between distantly related algal lineages. The recombinant sequences show highly contrasted level of divergence in the 5'- and 3'- regions of the gene, leading to significantly different tree topologies depending on the gene segment (5'- or 3'-) used for tree reconstruction. Consequently, the 5'-COI "barcoding" region (~ 650 bp) can be misleading for identification purposes, at least in the case of algal species that might have experienced historical hybridization events.ConclusionTaking into account the potential roles of phenotypic plasticity in evolution, we conclude that the TYP and LON forms represent examples of algae phenotypic diversification that enables successful adaptation to contrasting shallow- and deep-water marine environments, while the SHA form is very similar to S. cichorioides and should be considered a different species. Practical applications for algal management and conservation are briefly considered.

Dataset Information

Microsatellite and mitochondrial DNA homogeneity among phenotypically diverse crossbill taxa in the UK.

Publications

Microsatellite and mitochondrial DNA homogeneity among phenotypically diverse crossbill taxa in the UK.

Similar Datasets

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