Parental genome separation and asynchronous centromere division in interspecific F1 hybrids in Lathyrus.
Chromosomes were studied in root-tip metaphase cells of several F1 interspecific Lathyrus hybrids including: L. hirsutus x L. cassius (H x C), L. cassius x L. hirsutus (C x H), L. cassius x L. odoratus (C x O), and their parents, all with 2n = 2x = 14. Two types of morphologically distinct centromeres were identified in the hybrids on the basis of the degree of contraction of the primary constriction. At least 12 well-defined centromeres were seen in all cells of L. hirsutus, L. cassius and L. odoratus, and about 80% of cells had 14. The hybrids were more variable than the species. H x O contained between six and 14 well-defined centromeres, while cells of H x C, C x H and C x O all had seven well-defined and seven weakly defined centromeres. These were used as markers to plot their spatial disposition in two dimensions on metaphase spreads. In H x C, C x H and C x O the two types of centromeres showed a significant tendency to occupy two spatially distinct and concentrically arranged domains on the metaphase plate (P < 0.005). Owing to shortage of material subsequent work was restricted to H x C and C x H. Six or seven chromosomes of one parental genome were selectively labelled by in situ hybridization using biotinylated total genomic DNA from either parent as a probe. Moreover, there was a very strong correlation between centromere type and genomic origin (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Callimassia
M A
MA
Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, UK.
Murray
B G
BG
Hammett
K R
KR
Bennett
M D
MD
D002503:Centromere / Q000648:ultrastructure*; D007887:Fabaceae / Q000145:classification / Q000235:genetics*; D016678:Genome; D001467:Hordeum / Q000235:genetics; D006824:Hybridization, Genetic; D017403:In Situ Hybridization; D008677:Metaphase; D010946:Plants, Medicinal; D012434:Secale / Q000235:genetics; D013045:Species Specificity