Allotriploid Genotypic Assignment in Abalone Larvae by Detection of Microsatellite-Recombinant Genotypes

Abstract

Abalone species are different from most mollusks utilized in aquaculture as they are known to hybridize in laboratory-induced matings. Allotriploidization of hybrid abalone has not yet been studied, and methodology useful in verifying the genotypic condition of such allotriploids do not exist. Genotypic verification of hybridization and allotriploidization in a cross of Haliotis fulgens and Haliotis rufescens was performed utilizing 6 crossamplifying microsatellite loci. Five H. rufescens spawns were used in this experiment, dividing each spawn into control and experimental hybrid groups and further into diploids and triploids. Two microsatellite loci developed for H. fulgens and H. rufescens allowed for the genotypic identification of hybrids within diploid and triploids. To further verify the percentage of allotriploids within the genotypic hybrids in the triploid hybrid groups, microsatellite loci originally developed in Haliotis corrugata and Haliotis kamtschatkana were tested for crossamplification in H. fulgens and H. rufescens. Of 21 loci, 4 were chosen for this study based on their crossamplification, heterozygosity in the females, and centromere recombination frequencies. Allotriploids in triploid-hybrid larvae were then detected by identifying larvae with recombinant genotypes at any of those loci. One family had low success verification associated with reduced recombination frequencies for all loci in that family. These results demonstrate that allotriploid verification at larval stages is feasible but depends on the number of loci available, their crossamplification in the species, and their recombination frequencies.

Intraspecies and interspecies hybrids in Haliotis: natural and experimental evidence and its impact on abalone aquaculture

“…As pointed out by Bartley et al (2001), chromosome set manipulation can be combined with hybridization to increase the viability of hybrid fishes and to increase the developmental stability of hybrids during their early lifehistory stages. The first such study in abalone has recently been published by Hernández- Ibarra et al (2010). In this research, six microsatellite loci were used to verify hybridization and allotriploidization in larvae of the cross between H. fulgens and H. rufescens.…”

“…Four heterologous microsatellite loci developed for H. corrugata and H. kamtschatkana allowed for verification of the percentage of allotriploids within the genotypic hybrids in the triploid hybrid groups. Hernández- Ibarra et al (2010) discussed the feasibility of using microsatellite loci for allotriploid verification at larval stages depending on the number of loci available, their crossamplification success in the target species and their recombination frequencies. Further research in this area is needed to establish their practical use in hybrid abalone production.…”

“…(2001), chromosome set manipulation can be combined with hybridization to increase the viability of hybrid fishes and to increase the developmental stability of hybrids during their early life‐history stages. The first such study in abalone has recently been published by Hernández‐Ibarra et al. (2010).…”