Genome size correlates with reproductive fitness in seed beetles.
The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the 'C-value paradox'. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4-5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.
Animal Ecology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, Uppsala 75236, Sweden goran.arnqvist@ebc.uu.se.
Göran
http://orcid.org/0000-0002-3501-3376
G
Arnqvist
Animal Ecology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, Uppsala 75236, Sweden.
Ahmed
A
Sayadi
Animal Ecology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, Uppsala 75236, Sweden.
Elina
E
Immonen
Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, Uppsala 75236, Sweden.
Cosima
C
Hotzy
Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland.
Daniel
D
Rankin
Laboratory of Insect Natural Enemies, Department of Bioresource Sciences, Kyushu University, Fukuoka 812-8581, Japan Institute of Biological Control, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
Midori
M
Tuda
Department of Entomology, Texas A&M University, College Station, TX 77843 2475, USA.
Carl E
CE
Hjelmen
Department of Entomology, Texas A&M University, College Station, TX 77843 2475, USA.
J Spencer
JS
Johnston
D000818:Animals; D005075:Biological Evolution; D001517:Coleoptera / Q000235:genetics*; D005260:Female; D040961:Genetic Drift; D056084:Genetic Fitness; D059646:Genome Size; D049750:Genome, Insect; D008297:Male; D010802:Phylogeny; D012641:Selection, Genetic
Callosobruchus maculatus; population size; selfish DNA; sex chromosomes; sexual dimorphism; sperm competition