Miao Yunzheng, Yang Siqing, Jiang Yurong, Rong Junkang, Yu Jinsheng
The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, School of Agriculture and Food Science, Zhejiang A&F University, Linan, Hangzhou 311300, Zhejiang, People's Republic of China.
J Genet. 2018 Dec;97(5):1421-1431.
Nonrandom segregation ratios of alleles 'segregation distortion' can have a striking impact on transmission genetics, and with widespread availability of genetic markers has been shown to be a frequent phenomenon. To investigate the possible effect of genetic interaction on segregation distortion and genetic map construction, the segregation and mapping of genetic markers locatedon wheat chromosomes 1A and 1B were followed in four recombinant substitution line (RSL) populations, produced using four chromosome-arm substitution lines (CASLs 1AS, 1AL, 1BS and 1BL) of wild emmer ( var. , accession TTD140) in the background of the common wheat () cultivar Bethlehem (BLH), each crossed to BLH itself. Using these four RSL populations, four genetic maps of chromosome 1 arms were constructed. A total of 22 genetic markers representing 19 loci were assigned to chromosome 1A, and 32 markers representing 30 loci were assigned to 1B. For chromosome 1B, two linkage maps were also constructed using RFLP data of an F population derived from the same cross combination as the RSLs. The RSL and F maps varied in genetic distances, but showed the same linear order of DNA markers. Segregation analysis revealed strong selection against BLH alleles on chromosome 1B, skewing the allelic frequency distribution in favour of TTD in both F and RSL populations at all marker loci. On the contrary, strong selection against TTD alleles on chromosome 1A was detected for some loci in the BLH × CASL1AL RSLs, and their distribution was significantly skewed to BLH. F populations always showed more segregation distortion than the corresponding RSLs. More markers near the region of chromosome 1B shared by both CASL1BS and 1BL (∼55 cM on chromosome 1B across the centromere) showed significantly distorted segregation in the BLH × CASL1BL population than in thecorresponding BLH × CASL1BS populations. Six markers located on chromosome 1A region shared by CASL1AS and 1AL showed significantly distorted segregation in 1AL-RSL, while no marker showed distorted segregation in 1AS-RSL. These results indicated that genetic factor(s) in the centromere region cause the distorted segregation of genetic markers on wheat chromosome 1B.
等位基因的非随机分离比例(“分离畸变”)会对传递遗传学产生显著影响,并且随着遗传标记的广泛可得,已被证明是一种常见现象。为了研究基因互作对分离畸变和遗传图谱构建的可能影响,在四个重组代换系(RSL)群体中追踪了位于小麦1A和1B染色体上的遗传标记的分离和定位情况,这些群体是利用野生二粒小麦(变种,种质TTD140)的四个染色体臂代换系(CASL 1AS、1AL、1BS和1BL)在普通小麦()品种伯利恒(BLH)的背景下培育而成的,每个群体都与BLH自身杂交。利用这四个RSL群体,构建了1号染色体臂的四个遗传图谱。共有代表19个位点的22个遗传标记被定位到1A染色体上,代表30个位点的32个标记被定位到1B染色体上。对于1B染色体,还利用与RSL来自相同杂交组合的F群体的RFLP数据构建了两个连锁图谱。RSL图谱和F图谱在遗传距离上有所不同,但显示出相同的DNA标记线性顺序。分离分析显示,在1B染色体上对BLH等位基因存在强烈选择,在所有标记位点,F群体和RSL群体中的等位基因频率分布均偏向TTD。相反,在BLH×CASL1AL RSLs的某些位点检测到对1A染色体上TTD等位基因的强烈选择,其分布显著偏向BLH。F群体总是比相应的RSL群体表现出更多的分离畸变。在BLH×CASL1BL群体中,与CASL1BS和1BL共有的1B染色体区域(跨越着丝粒的1B染色体上约55 cM)附近的更多标记显示出比相应的BLH×CASL1BS群体更显著的分离畸变。位于CASL1AS和1AL共有的1A染色体区域的六个标记在1AL-RSL中显示出显著的分离畸变,而在1AS-RSL中没有标记显示出分离畸变。这些结果表明,着丝粒区域的遗传因素导致了小麦1B染色体上遗传标记的分离畸变。