沙地云杉与其近缘种间的GISH分析

以沙地云杉(Picea mongolica(H.Q.Wu)W.D.Xu)、白杄(P.meyeri Rehd.et Wils.)、红皮云杉(P.koraiensis Nakai)3种云杉属植物为材料,利用基因组原位杂交技术(GISH),用白杄和红皮云杉基因组DNA分别作探针与沙地云杉中期染色体进行杂交,分析3种云杉的亲缘关系,旨在进一步探讨沙地云杉的起源。结果表明:(1)3种云杉的染色体数目均为2n=24,核型类型为1A,大部分染色体为亚中部着丝粒;白杄和红皮云杉核型不对称系数分别为57.78%、57.64%,小于沙地云杉(58.75%)。(2)以白杄基因组DNA为探针时,在沙地云杉14条染色体上有明显杂交信号,信号位点主要位于着丝粒区、次缢痕处和短臂部位;以红皮云杉DNA为探针时,12条染色体上有明显杂交信号,主要位于着丝粒区、次缢痕处和长臂上,杂交信号分布范围和强度明显弱于白杄。研究认为,沙地云杉与白杄的亲缘关系较近,而与红皮云杉较远,该研究首次阐明沙地云杉非起源于白杄和红皮云杉的种间杂交。

GISH Analysis of Picea mongolica and Related Species

Picea mongolica, P. meyeri and P. koraiensis as research objects, the genomic DNA of P. meyeri and P. koraiensis were used respectively as the probes to hybridize with the mid chromosomes of P. mongolica by the Genomic In Situ Hybridization (GISH) to study the genetic relationship among the three Picea species, and demonstrate the origin of the P. mongolica. In this study, our results show that: (1) the chromosome numbers of all three Picea species were 2n=24 and the karyotype type was 1A, and most of the chromosomes were sub central centromere. The As.K% of P. meyeri and P. koraiensis were 57.78% and 57.64% respectively, which were lower than that of P. mongolica (58.75%). (2) The 14 chromosomes of P. mongolica showed obvious hybridization signals using P. meyeri genomic DNA as a probe, the stronger signal sites were mainly concentrated in the kinetochore domain, secondary constriction and short arms of the chromosomes. The obvious hybridization signal appeared on 12 chromosomes of P. mongolica using the P. koraiensis genomic DNA as the probe, the stronger signal was mainly located on the kinetochore domain, secondary constriction and long arms of the chromosomes, and the hybridization signal distribution range and intensity were weaker than that of P. meyeri. Therefore, our study shows that the genetic relationship of P. mongolica and P. meyeri were closed than that of P. koraiensis. Then, it was the first to prove that P. mongolica can not be produced by the hybridization between P. meyeri and P. koraiensis.