The study of hybridization processes within genus Sparganium L. Subgenus Xanthosparganium holmb. Based on data of next generation sequencing (NGS)

Abstract

The study represents the results of research of intragenic polymorphism in transcribed spacer ITS1 of the 35S rRNA genes in representatives of subgenus Xanthosparganium genus Sparganium which were obtained by means of locus-specific next generation sequencing on the platform Illumina MiSeq. It was shown that ribotype variations in studied samples generally correspond to the division of this genus into three sections Erecta (subgenus Sparganium), Natantia and Minima (subgenus Xanthosparganium). High level of intragenic polymorphism was revealed in S. hyperboreum, with ribotypes distributed among several groups. Genome of this species includes ribotypes which are typical for other species in subgenus Xanthosparganium. For two investigated S. glomeratum samples, there were no ribotypes similar to such ribotypes in other species of Natantia section. S. glomeratum has got ribotypes identical with S. hyperboreum of Minima section. This feature may be the evidence of ancient intersectional hybridization of these two species. Characteristics of rDNA in S. glomeratum are in favor of putting this species into Minima section. It was suggested that speciation processes within the genus could be based not only on hybridization but also went on in allopatric way. The fist statement is supported by the presence of similar and identical ribotypes in S. emersum, S. longifolium, S. gramineum and S. hyperboreum, the second as it was mentioned by other researchers, is due to close relationship between North American and Eurasian taxa.