The origin of multiple clones in the parthenogenetic lizard species Darevskia rostombekowi

Abstract

The all-female Caucasian rock lizard Darevskia rostombekowi and other unisexual species of this genus reproduce normally via true parthenogenesis. Typically, diploid parthenogenetic reptiles exhibit some amount of clonal diversity. However, allozyme data from D. rostombekowi have suggested that this species consists of a single clone. Herein, we test this hypothesis by evaluating variation at three variable microsatellite loci for 42 specimens of D. rostombekowi from four populations in Armenia. Analyses based on single nucleotide polymorphisms of each locus reveal five genotypes or presumptive clones in this species. All individuals are heterozygous at the loci. The major clone occurs in 24 individuals and involves three populations. Four rare clones involve one or several individuals from one or two populations. Most variation owes to parent-specific single nucleotide polymorphisms, which occur as heterozygotes. This result fails to reject the hypothesis of a single hybridization founder event that resulted in the initial formation of one major clone. The other clones appear to have originated via post-formation microsatellite mutations of the major clone.

Fig 1. Map of Armenia showing the localities from which populations of parthenogenetic Darevskia rostombekowi and bisexual parental species D. raddei and D. portschinskii were collected.

Sampling localities are indicated by the following colors: D. rostombekowi–yellow; D. raddei raddei–blue; D. raddei nairensis–red; D. portschinskii portschinskii–green; D. portschinskii nigrita–black. Numbers indicate populations: 1 –Gosh (40°42'20.3"N 45°00'57.7"E); 2 –Tsovak (40°10'45.0"N 45°37'22.7"E); 3 –Papanino (40°42'27.7"N 44°45'43.8"E); 4 –Spitak (40°48'50.0"N 44°16'48.7"E); 5 –Geghard (40°08'49.4"N 44°48'26.9"E); 6 –Goris (39°33'09.5"N 46°21'19.7"E); 7 –Doroga (39°22'53.9"N 46°21'06.6"E); 8 –Yeghegnadzor (39°47'48.4"N 45°19'52.4"E); 9 –Kelbajar (40°06'03.1"N 45°59'27.1"E); 10 –Tatev (39°23'13.2"N 46°15'11.2"E); 11 –Ayrivank (40°26'02.3"N 45°06'27.2"E); 12 –Bjni (40°27'42.6"N 44°39'07.3"E); 13 –Yerevan (40°10'37.0"N 44°36'09.3"E); 14 –Lchap (40°28'02.4"N 45°03'43.5"E); 15 –Lchashen (40°30'45.9"N 44°54'03.2"E); 16 –Pyunik (40°36'49.9"N 44°35'06.4"E); 17 –Zuar (40°04'39.0"N 46°13'47.0"E); 18 –Dzoraget (40°54'15.0"N 44°40'37.7"E).

Fig 2. Schematic representation of five genotypes formed by allelic combinations of microsatellite loci Du215, Du281, and Du323 in 42 individuals of Darevskia rostombekowi.

Parent-specific SNV markers are shown in yellow squares. Variable microsatellite clusters are shown in each of two alleles.

Fig 3. Genetic similarity between the sequences of alleles Du281 (a) and Du323 (b) for the species D. portschinskii (D. port), D. rostombekowi (D. rost) and D. raddei (D. rad).

NJ/p-distance/Pairwise deletions/IB = 500.