King J, Roberts L A, Kearsey M J, Thomas H M, Jones R N, Huang L, Armstead I P, Morgan W G, King I P
Institute of Biological Sciences, University of Wales, Aberystwyth, SY23 3DA, Wales, United Kingdom.
Genetics. 2002 May;161(1):307-14. doi: 10.1093/genetics/161.1.307.
A single chromosome of the grass species Festuca pratensis has been introgressed into Lolium perenne to produce a diploid monosomic substitution line 2n = 2x = 14. The chromatin of F. pratensis and L. perenne can be distinguished by genomic in situ hybridization (GISH), and it is therefore possible to visualize the substituted F. pratensis chromosome in the L. perenne background and to study chiasma formation in a single marked bivalent. Recombination occurs freely in the F. pratensis/L. perenne bivalent, and chiasma frequency counts give a predicted map length for this bivalent of 76 cM. The substituted F. pratensis chromosome was also mapped with 104 EcoRI/Tru91 and HindIII/Tru91 amplified fragment length polymorphisms (AFLPs), generating a marker map of 81 cM. This map length is almost identical to the map length of 76 cM predicted from the chiasma frequency data. The work demonstrates a 1:1 correspondence between chiasma frequency and recombination and, in addition, the absence of chromatid interference across the Festuca and Lolium centromeres.
草地羊茅（Festuca pratensis）的一条染色体已渗入多年生黑麦草（Lolium perenne）中，产生了一个二倍体单体代换系，2n = 2x = 14。通过基因组原位杂交（GISH）可以区分草地羊茅和多年生黑麦草的染色质，因此可以在多年生黑麦草背景中观察到被代换的草地羊茅染色体，并研究单个标记二价体中的交叉形成。重组在草地羊茅/多年生黑麦草二价体中自由发生，交叉频率计数得出该二价体的预测图距为76厘摩（cM）。还用104个EcoRI/Tru91和HindIII/Tru91扩增片段长度多态性（AFLP）对被代换的草地羊茅染色体进行了作图，生成了一个81 cM的标记图谱。该图距与根据交叉频率数据预测的76 cM图距几乎相同。这项工作证明了交叉频率与重组之间存在1:1的对应关系，此外，在草地羊茅和黑麦草的着丝粒之间不存在染色单体干涉。
