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Lack of variation at phosphoglucose isomerase (pgi) in bumblebees: implications for conservation genetics studies.

Ellis JS, Turner LM, Knight ME - PLoS ONE (2013)

Bottom Line: However, phosphoglucose isomerase (Pgi) has been proposed as a useful functional marker in the conservation genetics of invertebrates.We here report very low levels of Pgi variation in bumblebees rendering this locus to be of little use as an adaptive marker in a conservation genetics context in this group.Potential explanations for this lack of variation are considered.

View Article: PubMed Central - PubMed

Affiliation: School of Science and the Environment, Manchester Metropolitan University, Manchester, Greater Manchester, United Kingdom. j.ellis@mmu.ac.uk

ABSTRACT
Assessing genetic variation underlying ecologically important traits is increasingly of interest and importance in population and conservation genetics. For some groups generally useful markers exist for examining the relative role of selection and drift in shaping genetic diversity e.g. the major histocompatibility complex in vertebrates and self-incompatibility loci in plants. For invertebrates there is no such generally useful locus. However, phosphoglucose isomerase (Pgi) has been proposed as a useful functional marker in the conservation genetics of invertebrates. Where thermal microclimate varies, balanced polymorphisms may be maintained due to trade-offs between thermally stable and kinetically advantageous allelic forms. We here report very low levels of Pgi variation in bumblebees rendering this locus to be of little use as an adaptive marker in a conservation genetics context in this group. Potential explanations for this lack of variation are considered.

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Network showing the relation between phosphoglucose isomerase haplotypes for all regions (coding and non-coding).PC = B. pascuorum, HU = B. humilis, PT = B. pratorum, M = B. monticola, L = B. lapidarius. Numbers along the connecting lines indicate the number of mutated positions between haplotypes. Nodes are not proportional to haplotype frequencies.
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pone-0065600-g003: Network showing the relation between phosphoglucose isomerase haplotypes for all regions (coding and non-coding).PC = B. pascuorum, HU = B. humilis, PT = B. pratorum, M = B. monticola, L = B. lapidarius. Numbers along the connecting lines indicate the number of mutated positions between haplotypes. Nodes are not proportional to haplotype frequencies.

Mentions: Very few non-coding segregating sites were observed for either locus in any species (Table 2), although a microsatellite sequence was observed in Pgi in B. pratorum. In coding regions, a maximum of one segregating site (synonymous or non-synonymous) was observed in B. pascuorum, B. pratorum and B. lapidarius for Pgi and likewise few were observed for Pgm (Table 2). For comparison, estimates from Drosophila, where diversity is also low [10], are also provided (Table 2). Nucleotide diversity is similar for D. melanogaster and D. yakuba, but greater for D. simulans. The lack of intra-specific variation observed precluded assessment of selection by McDonald-Kreitman (MK) tests in most cases [30]; however, the number of fixed inter-specific non-synonymous and synonymous differences were calculated for completion. (Note that synonymous sequence divergence between species pairs varied from 1.7% (B. pascuorum & B. humilis) to 5.1% (B. lapidarius & B. pratorum) at Pgi and from1.0% (Bombus pascuorum & B. humilis) to 7.9% (B. lapidarius & B. pratorum) at Pgm. For Drosophila melanogaster & D. simulans synonymous site divergence at Pgi was 7.3%)). No large excess of non-synonymous substitutions was observed for any comparison at any locus and overall very little inter-specific divergence was observed, especially at non-synonymous sites (Table 3, Figures 3, 4, 5, 6). These results obviate the use of other tests of selection since within-species variation is so severely limited. In total across all species only 11 haplotypes were observed for complete sequences (including non-coding regions). When only coding regions were considered 8 haplotypes were observed. The relationship between haplotypes matched the known species phylogeny (Figures 3, 4, 5, 6). Across all species, 12 amino acid differences were observed (Table 4).


Lack of variation at phosphoglucose isomerase (pgi) in bumblebees: implications for conservation genetics studies.

Ellis JS, Turner LM, Knight ME - PLoS ONE (2013)

Network showing the relation between phosphoglucose isomerase haplotypes for all regions (coding and non-coding).PC = B. pascuorum, HU = B. humilis, PT = B. pratorum, M = B. monticola, L = B. lapidarius. Numbers along the connecting lines indicate the number of mutated positions between haplotypes. Nodes are not proportional to haplotype frequencies.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672202&req=5

pone-0065600-g003: Network showing the relation between phosphoglucose isomerase haplotypes for all regions (coding and non-coding).PC = B. pascuorum, HU = B. humilis, PT = B. pratorum, M = B. monticola, L = B. lapidarius. Numbers along the connecting lines indicate the number of mutated positions between haplotypes. Nodes are not proportional to haplotype frequencies.
Mentions: Very few non-coding segregating sites were observed for either locus in any species (Table 2), although a microsatellite sequence was observed in Pgi in B. pratorum. In coding regions, a maximum of one segregating site (synonymous or non-synonymous) was observed in B. pascuorum, B. pratorum and B. lapidarius for Pgi and likewise few were observed for Pgm (Table 2). For comparison, estimates from Drosophila, where diversity is also low [10], are also provided (Table 2). Nucleotide diversity is similar for D. melanogaster and D. yakuba, but greater for D. simulans. The lack of intra-specific variation observed precluded assessment of selection by McDonald-Kreitman (MK) tests in most cases [30]; however, the number of fixed inter-specific non-synonymous and synonymous differences were calculated for completion. (Note that synonymous sequence divergence between species pairs varied from 1.7% (B. pascuorum & B. humilis) to 5.1% (B. lapidarius & B. pratorum) at Pgi and from1.0% (Bombus pascuorum & B. humilis) to 7.9% (B. lapidarius & B. pratorum) at Pgm. For Drosophila melanogaster & D. simulans synonymous site divergence at Pgi was 7.3%)). No large excess of non-synonymous substitutions was observed for any comparison at any locus and overall very little inter-specific divergence was observed, especially at non-synonymous sites (Table 3, Figures 3, 4, 5, 6). These results obviate the use of other tests of selection since within-species variation is so severely limited. In total across all species only 11 haplotypes were observed for complete sequences (including non-coding regions). When only coding regions were considered 8 haplotypes were observed. The relationship between haplotypes matched the known species phylogeny (Figures 3, 4, 5, 6). Across all species, 12 amino acid differences were observed (Table 4).

Bottom Line: However, phosphoglucose isomerase (Pgi) has been proposed as a useful functional marker in the conservation genetics of invertebrates.We here report very low levels of Pgi variation in bumblebees rendering this locus to be of little use as an adaptive marker in a conservation genetics context in this group.Potential explanations for this lack of variation are considered.

View Article: PubMed Central - PubMed

Affiliation: School of Science and the Environment, Manchester Metropolitan University, Manchester, Greater Manchester, United Kingdom. j.ellis@mmu.ac.uk

ABSTRACT
Assessing genetic variation underlying ecologically important traits is increasingly of interest and importance in population and conservation genetics. For some groups generally useful markers exist for examining the relative role of selection and drift in shaping genetic diversity e.g. the major histocompatibility complex in vertebrates and self-incompatibility loci in plants. For invertebrates there is no such generally useful locus. However, phosphoglucose isomerase (Pgi) has been proposed as a useful functional marker in the conservation genetics of invertebrates. Where thermal microclimate varies, balanced polymorphisms may be maintained due to trade-offs between thermally stable and kinetically advantageous allelic forms. We here report very low levels of Pgi variation in bumblebees rendering this locus to be of little use as an adaptive marker in a conservation genetics context in this group. Potential explanations for this lack of variation are considered.

Show MeSH