Genome and chromosome disposition at somatic metaphase in a Hordeum × Psathyrostachys hybrid

Abstract

The distribution of chromosomes by centromeres and telomeres was studied in 100 squashed, somatic metaphases of a Hordeum vulgare (2 n =2x = 14) x Psathyrostachys fragilis (2 n = 2x = 14)hybrid. The chromosomes and chromosome arms were individually identified in each of the parental genomes by their Giemsa C-banding patterns. The P. fragilis chromosomes were more widely scattered on the metaphase plate, and were therefore, also, on average located further from the cell centre than the H. vulgare chromosomes. Within the parental genomes, the only exception from a random distribution of the chromosomes was that the two satellited chromosomes of H. vulgare were located closer to each other and to the cell centre than can be attributed to chance. This association was most clearly expressed for the telomeres of the chromosome arms carrying the satellites. The data suggest that the parental chromosome complements constitute separate units. This was supported by the observation that five cells had their genomes arranged side-by-side.

The genome organization and diversification of maize and its allied species revisited: evidences from classical and FISH-GISH cytogenetic analysis

“…2B). This phenomenon has been described in many interspecific or intrageneric hybrids, where a general different behavior of the two parental genomes occurred (Watanabe et al, 1976;Jouvé et al, 1977;Bennett, 1983;Linde-Larsen and Jensen, 1991;). In Zea, the asynchrony shown by each group of five bivalents can be interpreted as the consequence of the temporal separation of relic diploid genomes during the progress of meiosis.…”

Different timing and spatial separation of parental chromosomes in intergeneric somatic hybrids between Brassica napus and Orychophragmus violaceus

“…The spatial separation of parental genomes at metaphase has been reported in many intergeneric and interspecific hybrids from both plants (Finch et al, 1981;Gleba et al, 1987;Leitch et al, 1991;Linde-Laursen and Jensen, 1991) and animals (Zelesco and Graves, 1988;Brandriff et al, 1991). Genome separation potentially can influence chromosome behavior, gene expression, and DNA replication (Schwarzacher et al, 1992;Jackson, 2003).…”

Meiotic behaviour in the first interspecific hybrids between Brachiaria brizantha and Brachiaria decumbens

“…Genome separation of parental genomes at metaphase has been reported in many interspecific (Gleba et al. 1987) and intergeneric hybrids (Linde‐Laursen and Jensen 1991). According to Schwarzacher et al.…”