Microsatellites: A tool for evolutionary genetic studies of western Palearctic water frogs

Abstract

Genotypic variation at six of 67 microsatellite loci we developed from R a m ridibundu, containing di-or trinucleotidc simplesequence repeats, confirms the value of microsatellites as an evolutionary genetic tool for studying western Palearctic water frogs, a model system characterized by clonal reproduction in natural hybrid lineages. R. ridihunda, Rana lessonae. and their hemiclonal hybrid Rana esculenta, which transmits only its ridibunda genome to gametes, are highly variable in central Poland and northern Switzerland: with one exception (a locus that is part of a coding region), each locus was polymorphic in each taxon when scorable, and the number of alleles was high (in Swiss Zessonue-esculentu populations, 1-6 per locus, total 13. for ridihundu genomes; 1-9 per locus, total 23, for lessonue genomes; 3 shared by both genomes). Estimated repeat numbers ranged from 3 to 14 for trinucleotide-and from 6 to 27 for dinucleotide-repeats. Nonamplifying (null) alleles, problematic because they underestimate genotypic variability if undetected, occur in ridibunda genomes of Swiss R. esculenra at one locus: apparent lessonue null alleles at another locus were subsequently resolved for several segregating alleles evidenced by bands of much lower intensity. Two loci had multiple ridibunda alleles in Swiss R. escufentu and thus discriminate between hemiclones, with a resolution superior to that of allozymes. Adding these two loci to our protein electrophoretic data (7 loci) more than doublcd the number of hemiclones detected, showed that several allozyme-defined hemiclones are composites of multiple microsatellite hemiclones, and revealed clonal diversity in populations that are uniclonal by allozyme data. The extent to which microsatellite-defined hemiclones result from primary hybridizations or from subsequent mutations in ridibunda genomes of R. esculenra lineages remains to be determined. A sample of newly metamorphosed R. ridibundu from hybrid x hybrid matings collected at a Swiss population in the fall had a significant heterozygote excess at the two loci that varied in ridihunda genomes; this shows that most, probably all, of them originated from inter-rather than intrahemiclonal matings, in accord with the idea that the usual hybrid x hybrid inviability in lessonae-esculenfa systems is caused by deleterious recessive alleles on the clonally inherited ridihunda genomes. Three of four microsatellite loci tested amplified in most species of western Palearctic water frogs.

Hemiclone diversity in the hybridogenetic frog Rana esculenta outside the area of clone formation: the view from protein electrophoresis

“…Scribner et al. 1994) of clonal diversity in ridibunda genomes of R. esculenta lineages relative to allozymes: the addition of just two microsatellite loci that varied in R genomes to the allozyme data used here to discriminate between natural R. esculenta hemiclones has more than doubled the number of hemiclones distinguished at our Swiss study sites (Hotz et al. 2001); several allozyme‐defined hemiclones consist of more than one microsatellite‐defined hemiclone.…”

Contrasting reproductive strategies of triploid hybrid males in vertebrate mating systems

“… Primer Mix 1A – CA1b6, Ga1a19 redesigned (Arioli et al ., ), RlCA1b5, RlCA5 (Garner et al ., ), Rrid064A (Christiansen & Reyer, ) Primer Mix 1B – Re2CAGA3 (Arioli et al ., ), Res16, Res20 (Zeisset et al ., ) RlCA2a34 (Christiansen & Reyer, ) Primer Mix 2A – ReGA1a23, Rrid169A, Rrid059A redesigned (Christiansen & Reyer, ), Res22 (Zeisset et al ., ), Rrid013A (Hotz et al ., ) Primer Mix 2B – Re1CAGA10 (Arioli et al ., ), RlCA18 (Garner et al ., ), RlCA1a27, Rrid135A (Christiansen & Reyer, ). …”

From Clonal to Sexual Hybrids: Genetic Recombination via Triploids in All-Hybrid Populations of Water Frogs

“…4), RlCA2a34, and Rrid064A (Table 1). PCR 2 contained Res22 (Zeisset et al 2000), RlCA18 (Garner et al 2000), Rrid013A (Hotz et al 2001), Rrid059A redesigned (Hotz et al 2001 and Table 1: forward primer redesigned to extend the fragment amplified by 177 base pairs), Re1CAGA10 (Arioli 2007 ch. 4), RlCA1a27, ReGA1a23, Rrid169A, and Rrid135A (Table 1).…”