Fixed heterozygosis in a South-American parthenogenetic weevil revealed by Rad-Seq analysis

RODRIGUERO, MARCELA; CONFALONIERI, VIVIANA A.; ANALÍA A. LANTERI; GUZMÁN, NOELIA

Foz do Iguazú

Congreso; International Congress of Genetics; 2018

Sociedad Brasileira de Genética

Naupactus cervinus (Boheman) (Curculionidae, Naupactini) is a cosmopolitan weevil native to the Paranaense Forest. Currently, this species is parthenogenetic over its entire range, although in the 1950?s some bisexual lineages were collected in forest areas of north-eastern Argentina (Misiones province), and southern Brazil (Santa Catarina State). It is possible that these bisexual populations would have become extinct. This weevil displays high levels of genetic variation. Two divergent clades were identified, one ranging in forest areas (Forest clade), and the other in open vegetation areas (Grassland clade). Both of them have parthenogenetic females with high levels of heterozygosity in ribosomal sequences. Investigation of intraindividual variation in ITS1 sequences through cloning and posterior sequencing suggested that mating between both groups most likely occurred in the Paranaense Forest after secondary contact. Outcrossing would have fixed heterozygotes as a consequence of parthenogenesis. To further demonstrate heterozygosity of these individuals across the whole genome we accomplished a Rad-Seq analysis. We genotyped 80 individuals and obtained 75050 loci, 13899 SNPs and 11.5 % of missing data. Principal Component Analysis indicated that both Forest and Grassland clades are highly differentiated, and individuals coming from outcrossing (hereafter "OI") are intermediate between the two. However, those OI whose maternal lineage came from the Grassland clade are more similar to that group. A similar trend was observed for Forest OI. Heterozygosis was higher in OI individuals, followed by the Forest clade, being the Grassland clade the less variable group in our dataset. These results support the idea of outcrossing between Forest and Grassland clades when barriers related to Pleistocene glaciations vanished and the fixed heterozygosis across the genome of N. cervinus in populations from the Paranaense Forest.