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Nuclear ribosomal DNA ITS paralogs as evidence of recennt interspecific hybridization in the genus Ophrys [Orchidaceae]

100%

Gulyas G., Sramko G., Molnar A. V., Rudnoy S., Illyes Z., Balazs T., Bratek Z.

Acta Biologica Cracoviensia. Series Botanica

2005

tom 47

nr 2

Ophrys holubyana Andrasovszky (Orchidaceae), distributed in the Carpatho-Pannonian region, is generally believed to be of hybrid origin. Although its hybrid origin is broadly accepted by many authors, no molecular evidence has been found to support the hypothesis. The nuclear ribosomal DNA internal transcribed spacer (nrDNA ITS) region was sequenced from Ophrys holubyana, and from the presumed progenitor taxa: Ophrys fuciflora (Cr.) Rchb. and Ophrys bicornis Sadler ex Nendtvich. Nearly all the known populations in the Carpatho-Pannonian region were sampled, and the first data on the nrDNA ITS sequence of O. holubyana and O. bicornis are presented. Aligning the ITS sequences revealed no differences among the ten samples. After cloning the amplified ITS regions, eight discrete ITS paralogs with regularly appearing nucleotide differences could be partitioned, differing in only 6 base pairs. Paralog sequences were detected not only in O. holubyana but also in some populations of the two parent species, suggesting that O. fuciflora and O. bicornis in the Carpatho-Pannonian region are also partially of hybrid origin themselves, or influenced by introgression. The study suggests that nrlTS regions can be generally useful in the study of Ophrys systematics and phylogeography and for analyzing the hybrid zones of related Ophrys species groups.

Introgression of distant mitochondria into the genome of Gyrodactylus salaris: Nuclear and mitochondrial markers are necessary to identify parasite strains

59%

Zietara M. S., Rokicka M., Stojanovski S., Lumme J.

Acta Parasitologica

2010

tom 55

nr 1

20-28

Novel combinations of mitochondrial DNA (CO1) and internal transcribed spacers of nuclear ribosomal DNA (ITS) were detected among Gyrodactylus parasites on brown trout (Salmo trutta L.), rainbow trout (Oncorhynchus mykiss (Walbaum)), and Ohrid trout (Salmo letnica (Karaman)) from salmonid farms in Poland and Macedonia. Some clones differed from standard ITS only by ≤ 4 nucleotides, but they belonged to a mtDNA clade that differed from the Northern European lineages of G. salaris by d MCL = 0.266 ± 0.108 (maximum composite likelihood distance). The divergence of d MCL = 0.013 ± 0.005 within the alien mtDNA clade suggested introgression from an unknown maternal ancestor into the G. salaris Malmberg genome 137 to 57 kyr ago (or, less probably, repeated introgression). A comparable modern hybrid was detected based on permanently heterozygous ITS (28 bp/1264 = 2.2%) in a clone that is widespread throughout Finnish rainbow trout farms. This was a F1 hybrid of maternal G. pomeraniae Kuusela, Ziętara et Lumme (on roach, Rutilus rutilus (L.)) and G. lavareti Malmberg (on whitefish, Coregonus lavaretus (L.)). The mtDNA of the parental species differed by d MCL = 0.290 ± 0.130. The observations emphasize that both nuclear and maternally-inherited DNA markers are necessary to characterize sexually-produced lineages or clones of Gyrodactylus. The hybridization events demonstrated predict incongruence of mitochondrial vs. nuclear gene trees, i.e., reticulate evolution in species trees.

Ograniczanie wyników

1 Acta Biologica Cracoviensia. Series Botanica

1 Acta Parasitologica

1 Balazs T.

1 Bratek Z.

1 Gulyas G.

1 Illyes Z.

1 Lumme J.

1 Molnar A. V.

1 Rokicka M.

1 Rudnoy S.

1 Sramko G.

1 Stojanovski S.

1 Zietara M. S.

1 2010

1 2005

Wyniki wyszukiwania

Nuclear ribosomal DNA ITS paralogs as evidence of recennt interspecific hybridization in the genus Ophrys [Orchidaceae]

Introgression of distant mitochondria into the genome of Gyrodactylus salaris: Nuclear and mitochondrial markers are necessary to identify parasite strains