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Multiple paternity and hybridization in two smooth-hound sharks

2015; Nature Portfolio; Volume: 5; Issue: 1 Linguagem: Inglês

10.1038/srep12919

2045-2322

Ilaria A. M. Marino, Emilio Riginella, Michele Gristina, Maria Berica Rasotto, Lorenzo Zane, Carlotta Mazzoldi,

Fish biology, ecology, and behavior

Abstract Multiple paternity appears to be a common trait of elasmobranch mating systems, with its occurrence likely driven by convenience, due to females seeking to minimize the stress of male harassment. Here we use molecular markers to analyse the frequency of multiple paternity in two related viviparous sharks, Mustelus mustelus and Mustelus punctulatus . We first applied molecular methods to assign pregnant females, embryos and additional reference adults (N = 792) to one of the two species. Paternity analysis was performed using a total of 9 polymorphic microsatellites on 19 females and 204 embryos of M. mustelus and on 13 females and 303 embryos of M. punctulatus . Multiple paternity occurs in both species, with 47% of M. mustelus and 54% of M. punctulatus litters sired by at least two fathers. Female fecundity is not influenced by multiple mating and in 56% of polyandrous litters paternity is skewed, with one male siring most of the pups. Genetic analyses also revealed hybridization between the two species, with a M. punctulatus female bearing pups sired by a M. mustelus male. The frequency of polyandrous litters in these species is consistent with aspects of their reproductive biology, such as synchronous ovulation and possible occurrence of breeding aggregations.