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Wyszukujesz frazę "diploidization" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
FISH-aimed karyotype analysis in Aconitum subgen : aconitum reveals excessive rDNA sites in tetraploid taxa
Autorzy:
Sliwinska, Elwira
Musiał, Krystyna
Joachimiak, Andrzej
Grabowska-Joachimiak, Aleksandra
Hasterok, Robert
Opis:
The location of 5S and 35S rDNA sequences in chromosomes of four Aconitum subsp. Aconitum species was analyzed after fluorescence in situ hybridization (FISH). Both in diploids (2n = 2x = 16; Aconitum variegatum, A. degenii) and tetraploids (2n = 4× = 32; A. firmum, A. plicatum), rDNA repeats were localized exclusively on the shorter arms of chromosomes, in subterminal or pericentromeric sites. All analyzed species showed similar basal genome size (Cx = 5.31-5.71 pg). The most striking features of tetraploid karyotypes were the conservation of diploid rDNA loci and emergence of many additional 5S rDNA clusters. Chromosomal distribution of excessive ribosomal sites suggests their role in the secondary diploidization of tetraploid karyotypes.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
The phylogenetic position of Vincetoxicum pannonicum (Borhidi) holub supports the species’ allopolyploid hybrid origin
Autorzy:
Horvath, O.
Laczko, L.
Lisztes-Szabo, Z.
Molnar V., A.
Popiela, A.
Sramko, G.
Tematy:
allopolyploidy
concerted evolution
diploidization
gene tree incongruence
hybridization
Pannonian endemism
nrITS cloning
vulnerable species
Pokaż więcej
Wydawca:
Polskie Towarzystwo Botaniczne
Powiązania:
https://bibliotekanauki.pl/articles/2130712.pdf  Link otwiera się w nowym oknie
Opis:
The Pannonian endemic species Vincetoxicum pannonicum was described from specimens collected in Hungary and occurs at only few locations. It is considered “vulnerable” according to the International Red List. The chromosome set was reported to be tetraploid, and the species was hypothesized to be an allotetraploid hybrid of the Balkan species V. fuscatum and the Adriatic species V. hirundinaria subsp. adriaticum. We investigated the origin of V. pannonicum using molecular phylogenetic methods by separately analyzing the multicopy nuclear ribosomal internal transcribed spacer (nrITS) and the plastid-encoded trnH-psbA DNA regions and by evaluating discrepancies between the produced gene trees. Paralogs in the nrITS region clustered in two main groups, one of which was closest to V. fuscatum, and the other included V. hirundinaria subsp. adriaticum. According to trnH-psbA sequences, V. pannonicum and V. hirundinaria subsp. adriaticum formed a single group. Our results show that V. pannonicum diversified because of hybrid speciation, in which V. fuscatum was the pollen donor. We discovered a similar placement of V. maeoticum, which suggests a further hybridization event between V. fuscatum and a species of the V. hirundinaria group. Our genome-size estimate indicates almost sixfold larger genome size in V. pannonicum compared to the maternal diploid parent, suggesting hexaploidy; however, V. pannonicum is tetraploid. This may suggest cytological diploidization in the allopolyploid V. pannonicum. We observed substantial genetic distance between V. hirundinaria subsp. adriaticum and all other subspecies of V. hirundinaria, and we therefore propose that V. adriaticum should be regarded as a separate species.
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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