Genotype Reconstruction of Paternity in European Lobsters (Homarus gammarus)

Abstract

Decapod crustaceans exhibit considerable variation in fertilisation strategies, ranging from pervasive single paternity to the near-ubiquitous presence of multiple paternity, and such knowledge of mating systems and behaviour are required for the informed management of commercially-exploited marine fisheries. We used genetic markers to assess the paternity of individual broods in the European lobster, Homarus gammarus, a species for which paternity structure is unknown. Using 13 multiplexed microsatellite loci, three of which are newly described in this study, we genotyped 10 eggs from each of 34 females collected from an Atlantic peninsula in the south-western United Kingdom. Single reconstructed paternal genotypes explained all observed progeny genotypes in each of the 34 egg clutches, and each clutch was fertilised by a different male. Simulations indicated that the probability of detecting multiple paternity was in excess of 95% if secondary sires account for at least a quarter of the brood, and in excess of 99% where additional sire success was approximately equal. Our results show that multiple paternal fertilisations are either absent, unusual, or highly skewed in favour of a single male among H. gammarus in this area. Potential mechanisms upholding single paternal fertilisation are discussed, along with the prospective utility of parentage assignments in evaluations of hatchery stocking and other fishery conservation approaches in light of this finding.

Population genetic structure in European lobsters: implications for connectivity, diversity and hatchery stocking

“…Protocols for DNA extraction, primer synthesis, multiplexed PCR amplification of loci, fragment analysis and allele sizing followed those outlined in Ellis et al (2015c). Individuals were each screened at 15 microsatellites -12 from André & Knutsen (2010) …”

“…The locus HGA8 was found to be significantly deficient in heterozygotes, both globally (p < 0.001) and within the majority of geographic samples. This was the result of the failure of one or more alleles to amplify; null alleles at HGA8 were estimated to have a global frequency of 0.08, a maximum frequency of 0.2 among geographic samples, and were confirmed via a separate parentage analysis (Ellis et al 2015c). As a result, data for this locus were removed from the dataset ahead of analysis.…”

“…As a result, data for this locus were removed from the dataset ahead of analysis. A much rarer null allele at a second locus, HGC129, was detected via parentage (Ellis et al 2015c) but had an estimated global frequency of only 0.03. Genotype data at this locus were retained, since non-amplifying alleles of such low frequency generally have a negligible influence on population genetic analysis (Falush et al 2007).…”

High levels of polyandry, but limited evidence for multiple paternity, in wild populations of the western rock lobster (Panulirus cygnus)

“…Parentage studies have revealed that polyandry is widespread in decapods and that there is substantial variation in the extent of multiple paternity within and among species, ranging from zero in the European lobster, Homarus gammarus (Ellis et al, 2015) to 100% in the squat lobster, Munida sarsi (Bailie, Hynes, & Prodohl, 2011). For the most part, however, parentage studies on decapods have been conducted on crabs (Baggio et al, 2011;Jensen & Bentzen, 2012;Jossart et al, 2014;Koga, Henmi, & Murai, 1993;McKeown & Shaw, 2008;Pardo, Riveros, Fuentes, Rojas-Hernandez, & Veliz, 2016;Reaney, Maurer, Backwell, & Linde, 2012;Sainte-Marie, Gosselin, Sevigny, & Urbani, 2008).…”

“…By comparison, we know little about the mating system of lobsters (Ellis et al, 2015;Gosselin et al, 2005;Melville-Smith, de Lestang, Beale, Groth, & Thompson, 2009;Streiff, Mira, Castro, & Cancela, 2004), especially regarding female mating strategies and the prevalence of polyandry and multiple paternity in natural populations.…”