title: Genome size variation in the common frog Rana temporaria.
abstract: Genome size variation in the common frog (Rana temporaria) was investigated with flow cytometry in three latitudinally separated populations in Sweden to see whether it could provide a useful tool for sex-identification in this species. Depending on the sex and population, per cell DNA content (2C value) varied from 8.823 to 11.266 pg with a mean (+/- SE) 2C value of 9.961+/-0.083 pg. Analysis of variance revealed significant differences in genome size among populations and between sexes. Females had ca 3% larger genomes (x=10.133+/-0.068 pg) than males (x=9.832+/-0.068 pg) in all of the populations (sex x population interaction: P>0.10). Individuals from the southern-most population had significantly (x=9.330+/-0.081 pg) smaller genomes than those from the more northern populations (x=10.032+/-0.085 and x=10.584+/-0.085 pg, respectively). These results are in line with the interpretation that males in the common frog are the heterogametic sex, and that there exists large (up to 12%) geographic variation in genome size in this species. However, the sex differences in the genome size are too small to be useful in individual sex identification.
authors.affiliation: Ecological Genetics Research Unit, Dept of Biological and Environmental Science, University of Helsinki, Finland. chikako.matsuba@helsinki.fi
authors.forename: Chikako
authors.initials: C
authors.lastname: Matsuba
authors.forename: Juha
authors.initials: J
authors.lastname: Merilä
mesh_terms: D000818:Animals; D003627:Data Interpretation, Statistical; D005260:Female; D005434:Flow Cytometry; D014644:Genetic Variation; D005828:Genetics, Population; D016678:Genome; D008297:Male; D011896:Rana temporaria / Q000235:genetics*