Darren Monckton sexual selection of male horn size

natural selection should drive a sexually selected feature to fixation? • why are many

• 1, 750 sheep monitored and 5, 880 sheep sampled over a 21

horn variation in males is largely driven by variants in the RXFP 2 gene

horn variation in males is driven by variants in the RXFP 2 gene 2

male reproductive success relative male reproductive success Normal. . . Scurred. . . 0

male survival relative male survival Normal. . . Scurred. . . 1. 2 0.

fitness ~ survival + reproductive success

male fitness relative male fitness Normal. . . Scurred. . . 0 0. 0

a heterozygote advantage • a heterozygote advantage for male sheep maintains RXFP 2 diversity

Darwin’s Galapagos island finches • whole-genome sequencing of 120 individuals representing all of the

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Darren Monckton sexual selection of male horn size in Soay sheep

inter-sex sexual selection

intra-sex sexual selection

natural selection should drive a sexually selected feature to fixation? • why are many sexually selected traits not driven to fixation? • trait is driven by variation in many different genes with small effects and complex interactions • trait is constrained by other fitness effects

St Kilda

Soay sheep

winter

coat colour variation

horn variation

rutting

a highly studied population

• 1, 750 sheep monitored and 5, 880 sheep sampled over a 21 -year period

horn variation in males is largely driven by variants in the RXFP 2 gene Ho+/Ho+ Ho. P/Ho. P Ho+/Ho. P/Ho. P

horn variation in males is driven by variants in the RXFP 2 gene 2 0 0 1 8 0 1 6 0 1 4 0 1 2 0 1 0 0 horn base circumference (mm) horn length (mm) 4 0 0 3 6 0 3 2 0 2 8 0 2 4 0 2 0 0 Ho+/Ho + Ho+/H o. P Ho. P/H o. P RFXP 2 genotype Ho+/Ho + Ho+/H o. P Ho. P/H o. P

male reproductive success relative male reproductive success Normal. . . Scurred. . . 0 0. 3 0. 6 0. 9 • large horned males produce the most offspring in any one season 1. 2

male survival relative male survival Normal. . . Scurred. . . 1. 2 0. 9 0. 6 0. 3 • large horned males are the most likely to die during any one year 0

fitness ~ survival + reproductive success

male fitness relative male fitness Normal. . . Scurred. . . 0 0. 0 45 0. 0 9 0. 1 35 0. 1 8 0. 2 25 • intermediate horned males produce the most offspring during their lifetime

a heterozygote advantage • a heterozygote advantage for male sheep maintains RXFP 2 diversity • effects on survival constrain horn size

Darwin’s Galapagos island finches

Darwin’s Galapagos island finches • whole-genome sequencing of 120 individuals representing all of the Darwin’s finch species and two close relatives • phylogenetic analysis reveals important discrepancies with the phenotype-based taxonomy • variants in ALX 1 affect craniofacial development and beak shape diversity