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Intrapopulation genome size variation in D. melanogaster reflects life history variation and plasticity.

Ellis LL, Huang W, Quinn AM, Ahuja A, Alfrejd B, Gomez FE, Hjelmen CE, Moore KL, Mackay TF, Johnston JS, Tarone AM - PLoS Genet. (2014)

Bottom Line: We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates.Expression data implicate differences in metabolism that correspond to genome size variation.These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology, Texas A&M University, College Station, Texas, United States of America.

ABSTRACT
We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions.

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Related in: MedlinePlus

Genomic relationship among and between the large and small genome groups.(A) A heat map depicting the genomic relationship between DGRP lines. Genome size is ordered decreasingly from left to right and bottom to top. The strains in the groups are indicated as the red and blue rectangles on the top of the heat map. (B) Histograms showing genomic relationships within and between the genome size groups.
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pgen-1004522-g003: Genomic relationship among and between the large and small genome groups.(A) A heat map depicting the genomic relationship between DGRP lines. Genome size is ordered decreasingly from left to right and bottom to top. The strains in the groups are indicated as the red and blue rectangles on the top of the heat map. (B) Histograms showing genomic relationships within and between the genome size groups.

Mentions: It is possible that genotype is confounded with genome size. For example, if co-adapted suites of traits are associated with specific chromosomes of different sizes, strains with small genome sizes may also have distinct genotypically correlated phenotypes. If this is the case, we expect lines within the large or small genome groups would be more closely related to each other than lines between the groups. Indeed, genome size is significantly correlated with inversion karyotypes in the DGRP, and lines with the same inversion karyotypes are slightly more related to each other [33]. However, inversions clearly do not completely explain genome size variation, accounting for only ∼0.5 Mb of the variation in genome size [33]. To address the concern of relatedness among strains of atypical genome size, we evaluated the pair-wise genomic relatedness among lines. Relatedness between lines within the large and small genome size groups is not higher than that between groups, suggesting that the large and small genome lines form a genetically homogeneous pool rather than two separate clusters (Figure 3). This analysis, in combination with the fact that the aforementioned mixed models were designed to account for any confounding cryptic relationship among the lines, clearly suggests that there are correlations of genome size with life history traits that are independent of potential confounding genotypic effects at a broad genome-wide scale.


Intrapopulation genome size variation in D. melanogaster reflects life history variation and plasticity.

Ellis LL, Huang W, Quinn AM, Ahuja A, Alfrejd B, Gomez FE, Hjelmen CE, Moore KL, Mackay TF, Johnston JS, Tarone AM - PLoS Genet. (2014)

Genomic relationship among and between the large and small genome groups.(A) A heat map depicting the genomic relationship between DGRP lines. Genome size is ordered decreasingly from left to right and bottom to top. The strains in the groups are indicated as the red and blue rectangles on the top of the heat map. (B) Histograms showing genomic relationships within and between the genome size groups.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109859&req=5

pgen-1004522-g003: Genomic relationship among and between the large and small genome groups.(A) A heat map depicting the genomic relationship between DGRP lines. Genome size is ordered decreasingly from left to right and bottom to top. The strains in the groups are indicated as the red and blue rectangles on the top of the heat map. (B) Histograms showing genomic relationships within and between the genome size groups.
Mentions: It is possible that genotype is confounded with genome size. For example, if co-adapted suites of traits are associated with specific chromosomes of different sizes, strains with small genome sizes may also have distinct genotypically correlated phenotypes. If this is the case, we expect lines within the large or small genome groups would be more closely related to each other than lines between the groups. Indeed, genome size is significantly correlated with inversion karyotypes in the DGRP, and lines with the same inversion karyotypes are slightly more related to each other [33]. However, inversions clearly do not completely explain genome size variation, accounting for only ∼0.5 Mb of the variation in genome size [33]. To address the concern of relatedness among strains of atypical genome size, we evaluated the pair-wise genomic relatedness among lines. Relatedness between lines within the large and small genome size groups is not higher than that between groups, suggesting that the large and small genome lines form a genetically homogeneous pool rather than two separate clusters (Figure 3). This analysis, in combination with the fact that the aforementioned mixed models were designed to account for any confounding cryptic relationship among the lines, clearly suggests that there are correlations of genome size with life history traits that are independent of potential confounding genotypic effects at a broad genome-wide scale.

Bottom Line: We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates.Expression data implicate differences in metabolism that correspond to genome size variation.These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology, Texas A&M University, College Station, Texas, United States of America.

ABSTRACT
We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions.

Show MeSH
Related in: MedlinePlus