RT Journal Article SR Electronic T1 Sex-specific additive genetic variances and correlations for fitness in a song sparrow (Melospiza melodia) population subject to natural immigration and inbreeding JF bioRxiv FD Cold Spring Harbor Laboratory SP 272138 DO 10.1101/272138 A1 Matthew E. Wolak A1 Peter Arcese A1 Lukas F. Keller A1 Pirmin Nietlisbach A1 Jane M. Reid YR 2018 UL http://biorxiv.org/content/early/2018/05/15/272138.abstract AB Quantifying sex-specific additive genetic variance (VA) in fitness, and the cross-sex genetic correlation (rA), is pre-requisite to predicting evolutionary dynamics and the magnitude of sexual conflict. Quantifying VA and rA in underlying fitness components, and multiple genetic consequences of immigration and resulting gene flow, is required to identify mechanisms that maintain VA in fitness. However, these key parameters have rarely been estimated in wild populations experiencing natural environmental variation and immigration. We used comprehensive pedigree and life-history data from song sparrows (Melospiza melodia) to estimate VA and rA in sex-specific fitness and underlying fitness components, and to estimate additive genetic effects of immigrants as well as inbreeding depression. We found substantial VA in female and male fitness, with a moderate positive cross-sex rA. There was also substantial VA in adult reproductive success in males but not females, and moderate VA in juvenile survival but not adult survival. Immigrants introduced alleles for which additive genetic effects on local fitness were negative, potentially reducing population mean fitness through migration load, yet alleviating expression of inbreeding depression. Substantial VA for fitness can consequently be maintained in the wild, and be concordant between the sexes despite marked sex-specific VA in reproductive success.