Meiotic behaviour of individual chromosomes in allotriploid Alstroemeria hybrids

Abstract

Chromosome association and chiasma formation were studied in pollen mother cells at metaphase I of four allotriplod BC1 plants (2n ¼ 3x ¼ 24) obtained from the backcross of the hybrid Alstroemeria aurea  A. inodora with its parent A. inodora. We distinguished the chromosomes of both parental species by genomic in situ hybridization (GISH), whereas the individual chromosomes were identified on the basis of their multicolour FISH banding patterns obtained after a second hybridization with two species-specific satellite repeats as probes. All the four BC1 plants possessed two genomes of A. inodora and one of A. aurea. Variable numbers of recombinant chromosomes, resulting from meiotic recombination in the interspecific hybrid, were present in these plants. The homologous A. inodora chromosomes generally formed bivalents, leaving the homoeologous A. aurea chromosomes unassociated. High frequencies of trivalents were observed for the chromosome sets that contained recombinant chromosomes, even when the recombinant segments were small. Chromosome associations in the trivalents were restricted to homologous segments. The implications of the absence of homoeologous chromosome pairing on gamete constitution and prospects for introgression in Alstroemeria are discussed.

Analysis of introgression of the Tulipa fosteriana genome into Tulipa gesneriana using GISH and FISH

“…More information on chromosome rearrangements and the origin of particular chromosomes in hybrids can be obtained by simultaneously using a total genomic DNA probe and chromosome-speciWc DNA probes for in situ hybridization. The total genomic DNA probe is used to distinguish genomes, whereas the chromosome-speciWc probes are used to identify pairs of mitotic chromosomes or to visualize pairing of homologous chromosomes during meiosis-for example, in the interspeciWc hybrids of Alstromeria (Kamstra et al 1999(Kamstra et al , 2004 and Lilium (Lim et al 2001).…”

Genealogical relationships of southern Ontario polyploid unisexual salamanders (genus Ambystoma) inferred from intergenomic exchanges and major rDNA cytotypes

“…We used GISH to examine intergenomic exchanges in 110 unisexual individuals that included larvae and adults collected from 18 isolated populations. Although sequential and simultaneous GISH/FISH have been applied to reveal alien chromatin introgression and genetic identification of alien chromosomes in plants (Moscone et al 1996, Dong et al 2001, Kamstra et al 2004, Zheng et al 2006, no such experimentations have been attempted in any vertebrates that have a hybrid origin. For better resolution, we tentatively combined FISH-rDNA and GISH sequentially or simultaneously for most specimens to identify both genomic constitutions and major rDNA cytotypes on the same spreads.…”

Karyotype study in Luzuriaga radicans (Liliales: Luzuriagaceae)

“…These data are additional to the presence of asymmetric and bimodal karyotypes, and to the resemblances in karyotype morphology according to the one described in the present work for the intercontinental species L radians, L. parviflora and L. marginata. In the future, additional research using conventional and/or molecular cytogenetic techniques, previously performed for the genera belonging to the closely related family Alstroemeriaceae (Buitendijk et al 1997;Zhou et al 2003;Kamstra et al 2004;PalmaRojas et al 2007) should be done including all intercontinental taxa of Luzuriaga and their probable hybrids, which may deliver interesting insights on chromosome evolution within this Gondwanean genus.…”