Genetic certification of presumed hybrids of blue x red abalone (Haliotis fulgens Philippi and H. rufescens Swainson)

Abstract

Presumed hybrids between Haliotis rufescens and H. fulgens abalones, produced in a commercial abalone laboratory, were evaluated for progeny viability, gonad characteristics and for their 'true' status as hybrids by means of allozyme and microsatellite analyses. Four out of 10 evaluated allozyme loci proved to be useful for the genetic certi¢cation of hybrids, Gpi, Mdh-1, Mdh-2 and Sod, as they had exclusive alleles for each of the abalone reference species from which the presumed hybrids were produced. Three microsatellite loci were also evaluated for their usefulness in abalone hybrid certi¢cation. Two were not useful for hybrid certi¢cation as the reference abalone species shared some of the same alleles. The third loci (Hka 56) also had shared alleles between the two species, but at very di¡erent frequencies. Therefore, this permitted a presumptive certi¢cation of hybrids, which, however, was not error-proof as two allozyme certi¢ed hybrids were wrongly classi-¢ed as H. rufescens rather than as hybrids. Progeny viability of the only female certi¢ed to be a hybrid was signi¢cantly lower compared with one viability of the other females spawned, which were certi¢ed as H. rufescens. However, the number of eggs spawned by the only certi¢ed hybrid female was as large as those spawned by females certi¢ed as H. rufescens. Gonads of abalones sampled for the macroscopic appearance of sterility indicated that in the absence of any gonad development, no distinctive difference allows for hybrid identi¢cation, as there were undi¡erentiated individuals that were both hybrid and non-hybrid. On the other hand, two certi¢ed hybrid males were characterized by spermatocytes being the most abundant gamete type, although one had some spermatozoa present, indicating only partial sterility. Among the two female hybrids found, vitellogenesis was observed to proceed up to vitellogenic oocytes.

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

“…Backcrossing between hybrid females and H. rufescens males was conducted to estimate progeny viability, resulting in significantly lower survival rates for trochophores and postlarvae than those observed from non-hybrid females. The survival rate of hybrid trochophore larvae (20 h old) was 4.5%, whereas the survival rate of late veliger larvae (120 h old) was only 2.9%, which was significantly lower compared with the 62.2 and 70.4% registered in progeny from pure crosses of H. rufescens (Hernández- Ibarra et al 2005).…”

“…Interestingly, phylogenetic relationships among California species suggested by haemocyanin affinity analyses (Meyer 1967), protein electrophoresis (Brown 1993), sperm lysin DNA sequences (Lee & Vacquier 1992;Lee et al 1995), DNA egg receptor protein sequence vitelline envelope receptor for lysin gene (VERL) , Interval Transcribed Sequence (Coleman & Vacquier 2002) and haemocyanin sequences (Streit et al 2006) show close relationships (genetic proximity) between these species. More recent studies by Ibarra et al (2005) have produced and confirmed hybrids between H. rufescens $ and H. fulgens # on Mexico's commercial abalone farms, and have analysed the gametes of hybrid adult abalone (4-4.5 years old). The results show normal ovogenesis in hybrid females, whereas hybrid males show abnormal spermatogenesis and partial sterility.…”

Early identification of hybrids of Indian major carp, Labeo rohita and Catla catla using nuclear marker-based multiplex PCR

“…Previous studies using allozymes indeed described the genetic difference between the hybrids and their parental species (Brown and Murray, 1992;Hoshikawa et al, 1998;Ibarra et al, 2005;Ahmed et al, 2008). However, the use of allozyme loci failed to provide a sufficient genetic basis of hybrids, probably due to the less informative nature of allozyme loci.…”

Phenotype characterization of interspecific hybrid abalone Haliotis asinina and Haliotis squamata seed

“…Hibridisasi interspesifik selain dihadapkan pada kendala asinkronisasi pemijahan, juga ketidaksamaan daya tetas (Lafarga-De la Cruz et al, 2012), dan viabilitas yang lebih rendah (Ibarra et al, 2005). Seperti yang telah dijelaskan sebelumnya, pada penelitian ini terjadi pula kendala asinkronisasi pemijahan, selain itu terjadi abnormalitas pada perkembangan embrionya.…”