title: Multiple paternity and hybridization in two smooth-hound sharks.
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.
authors.affiliation: Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Ilaria A M
authors.initials: IA
authors.lastname: Marino
authors.affiliation: Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Riginella
authors.affiliation: IAMC-CNR, via Luigi Vaccara 61, 91026 Mazara del Vallo (TP), Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Gristina
authors.affiliation: Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Maria B
authors.initials: MB
authors.lastname: Rasotto
authors.affiliation: Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zane
authors.affiliation: Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Mazzoldi
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005260:Female; D005298:Fertility / Q000235:genetics; D056426:Genetic Loci; D006824:Hybridization, Genetic / Q000235:genetics*; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D009693:Nucleic Acid Hybridization; D010334:Paternity; D016133:Polymerase Chain Reaction; D012754:Sharks / Q000235:genetics*
chemical_list: D004247:DNA