Kamstra S A, de Jong J H, Jacobsen E, Ramanna M S, Kuipers A G J
Laboratory of Plant Breeding, The Graduate School of Experimental Plant Sciences, Wageningen University, PO Box 386, 6700 AJ Wageningen, The Netherlands.
Heredity (Edinb). 2004 Jul;93(1):15-21. doi: 10.1038/sj.hdy.6800465.
Chromosome association and chiasma formation were studied in pollen mother cells at metaphase I of four allotriplod BC1 plants (2n=3x=24) obtained from the backcross of the hybrid Alstroemeria aurea x 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.
对从杂交种六出花（Alstroemeria aurea）×无香六出花（A. inodora）与其亲本无香六出花回交获得的4株异源三倍体BC1植株（2n = 3x = 24）减数第一次分裂中期的花粉母细胞中的染色体联会和交叉形成进行了研究。我们通过基因组原位杂交（GISH）区分了两个亲本物种的染色体，而在与两种物种特异性卫星重复序列作为探针进行第二次杂交后，根据其多色荧光原位杂交（FISH）带型对单个染色体进行了鉴定。所有4株BC1植株都拥有两个无香六出花的基因组和一个六出花的基因组。这些植株中存在因种间杂种减数分裂重组而产生的数量可变的重组染色体。无香六出花的同源染色体通常形成二价体，而异源的六出花染色体不发生联会。对于包含重组染色体的染色体组，即使重组片段很小，也观察到了高频率的三价体。三价体中的染色体联会仅限于同源片段。讨论了异源染色体配对缺失对六出花配子构成的影响以及渐渗的前景。
