Indeterminate Meiotic Restitution (IMR): a novel type of meiotic nuclear restitution mechanism detected in interspecific lily hybrids by GISH
Indeterminate Meiotic Restitution (IMR): a novel type of meiotic nuclear restitution mechanism detected in interspecific lily hybrids by GISH
复制标题
DOI：
10.1007/s001220100638
复制
发表时间：
2001-08-01
影响因子：
5.4
通讯作者：
van Tuyl, JM
中科院分区：
文献类型：
--
作者：
Lim, KB;Ramanna, MS;van Tuyl, JM
使用DNA原位杂交方法（GISH和FISH）对三个二倍体百合品种（2n=2x=24）和三个二倍体种间杂种（2n=2x=24）的小孢子发生进行了详细分析。在简历中。 Gelria（长花百合；L 基因组）、Connecticut King 和 Mont Blanc（都是亚洲杂种；A 基因组）减数分裂是规则的，并且仅形成单倍体配子，而 L. longiflorumx 亚洲杂种（LA）之间的三个种间杂种显示减数分裂核恢复和可染色 2n 花粉形成的可变频率，范围为 3% 至 30%。通过GISH和FISH对LA杂种的减数分裂染色体行为进行分析表明：（1）亲本染色体在PMC中可以清楚地区分为单价、半二价和二价； (2) 在一些 PMC 中，整个补体以单价或半二价形式存在，它们有可能在第一次分裂期间等分分裂（在着丝粒分裂之后），从而导致第一次分裂恢复 (FDR) 配子； (3) 然而，更常见的是，在同一个 PMC 中，单价和半二价等分，而二价同时还原分离，产生 2n 配子，这可能与众所周知的 FDR 或 SDR 2n 配子不同。我们将这种新型恢复机制称为不确定减数分裂恢复（IMR）。为了证实IMR配子的发生，通过原位杂交分析了8个三倍体BC的染色体组成，通过原位杂交分析了产生LA杂种的2n配子与亚洲杂种亲本回交所衍生的后代。结果表明，有七种 BC 植物的 FDR 2n 配子（无论有或没有同源重组）均具有功能，而在一种情况下，由 IMR 产生的 2n 配子具有功能。在后者中，有证据表明通过同源交换以及同源染色体的分类发生了基因重组。 IMR 2n 配子的一个奇特特征是，虽然它向 BC1 后代传递了 24 条整倍体染色体，但从两个亲本物种传递的染色体数量不同：9 条 L 基因组染色体和 15 条 A 基因组染色体，而不是各 12 条。
A detailed analysis of microsporogenesis was carried out in three diploid lily cultivars (2n=2x=24) and three diploid interspecific hybrids (2n=2x=24) using DNA in situ hybridisation methods (GISH and FISH). In cvs. Gelria (Lilium longiflorum; L genome), Connecticut King and Mont Blanc (both Asiatic hybrids; A genome) meiosis was regular and only haploid gametes were, formed while the three interspecific hybrids between L. longiflorumxAsiatic hybrid (LA) showed a variable frequency of meiotic nuclear restitution and stainable 2n-pollen formation ranging from 3% to 30%. An analysis of meiotic chromosome behaviour of the LA hybrids through GISH and FISH revealed that: (1) the parental chromosomes could be clearly discriminated into univalents, half-bivalents and bivalents in the PMCs; (2) in some of the PMCs the entire complement was present either as univalents or half-bivalents which had the potential to divide equationally (following centromere division) during the first division leading to first division restitution (FDR) gametes; (3) more frequently, however, in one and the same PMC the univalents and half-bivalents divided equationally whereas the bivalents disjoined reductionally at the same time giving rise to 2n-gametes that could vary from the well-known FDR or SDR 2n-gametes. We indicate this novel type of restitution mechanism as Indeterminate Meiotic Restitution (IMR). In order to confirm the occurrence of IMR gametes, the chromosome constitutions of eight triploid BC, progenies derived from backcrossing the 2n-gamete producing the LA hybrids to the Asiatic hybrid parents were analysed through in situ hybridisation. The results indicated that there were seven BC, plants in which FDR 2n-gametes, with or without homoeologous recombinations, were functional, whereas in one case the 2n-gamete resulting from IMR was functional. In the latter, there was evidence for the occurrence of genetic recombination through homoeologous crossing-over as well as through the assortment of homoeologous chromosomes. A singular feature of the IMR 2n-gamete was that although it transmitted a euploid number of 24 chromosomes to the BC1 progeny, the number of chromosomes transmitted from the two parental species was dissimilar: 9 L-genome chromosomes and 15 A-genome chromosomes instead of 12 of each.