PCR-based nuclear markers identify alien blue mussel (Mytilusspp.) genotypes on the west coast of Canada

Abstract

Two blue mussel sibling species, Mytilus edulis and Mytilus galloprovincialis, have been imported to Pacific northwest waters in separate attempts to circumvent early mortality experienced by the native species (Mytilus trossulus) when cultured. Here we describe two novel markers based on the polymerase chain reaction that discriminate the two non-native, or alien, mussel species from the native species. The two markers are inherited in a Mendelian fashion, show no evidence of close linkage, and are highly diagnostic. To screen British Columbian mussel populations for the presence of the alien species, we assayed genotypes at the two marker loci in 482 subtidal mussels collected at 12 sites. Animals with at least one alien allele were present at 9 of 12 sampling sites with an overall frequency of 6.2%. The distribution of alien alleles at the two marker loci differed among sampling sites, suggesting differential introgression. The widespread incidence of alien alleles, combined with evidence of extensive hybridization between the alien and native species, indicates that the introduced alleles will probably persist in British Columbia mussels for some time.

Identification of DeltaN Isoform and Polyadenylation Site Choice Variants in Molluscan p63/p73-Like Homologues

“…Each of the three M. trossulus gill DNA samples showed three bands at 180, >200 and 280 nt, while each of the three M. edulis gill DNA samples showed a doublette at approximately 180 and 200 nt and a third band at 480 nt (Figure 1). This result compares well with results obtained previously by Heath et al (1995) taking into account paired bands that cannot be completely resolved by standard agarose electrophoresis.…”

“…The identities of the mussel species were confirmed by ITS PCR and RFLP with HhaI (Heath et al, 1995). Each of the three M. trossulus gill DNA samples showed three bands at 180, >200 and 280 nt, while each of the three M. edulis gill DNA samples showed a doublette at approximately 180 and 200 nt and a third band at 480 nt (Figure 1).…”

“…The internal transcribed spacer (ITS) region of the ribosomal RNA genes was amplified using a method developed by (Heath et al, 1995) with the following modifications: 1 μl of template DNA was amplified in a 25 μl-reaction containing 2 mM MgCl 2 , 5 mM each ITS primer (Table 1) and 1 U Taq polymerase (Invitrogen). Thermal cycling was performed as follows: 94 o C for 10 min, 10 cycles of 94 o C for 30", 53 o C for 30", 72 o C for 1', 20 cycles of 94 o C for 30", 55 o C for 30", 72 o C for 1', and final extension for 7' at 72 o C. 5 μl of the PCR reaction was transferred to a fresh reaction tube and supplemented with 7.5 μl dH 2 O, 1.5 μl React 2 buffer and 1 μl HhaI enzyme (Invitrogen).…”

Oxygen isotope ratios in the shell of <i>Mytilus edulis</i>: archives of glacier meltwater in Greenland?

“…kit (Omega Biotek, Norcross, GA, USA) following the manufacturer's protocol except for increased digestion time from 5 to 30 h (Doherty et al, 2007). The protocol for the two RFLP markers, Mal-1 treated with restriction enzyme SpeI and ITS followed by restriction with HhaI, is outlined in Rawson et al (2001) and Heath et al (1995), respectively. The applications of Glu-5 and Me 15/16 markers are outlined in Rawson et al (1996a) and Inoue et al (1995), respectively (Table 2).…”

Evolutionary implications of discordant clines across the Baltic Mytilus hybrid zone (Mytilus edulis and Mytilus trossulus)

“…ITS alleles specific to M. edulis and M. trossulus were detected based on a PCR-RFLP approach according to Heath et al (1995). As the ITS locus is a multicopy operon (Riginos et al, 2002), it was not analyzed for those parameters assuming a Mendelian inheritance (that is, Hardy-Weinberg equilibrium, cline analysis).…”