Assignment of molecular linkage groups to soybean chromosomes by primary trisomics

Abstract

Gene-linkage groups (classical linkage groups, CLGs; molecular linkage groups, MLGs) and chromosome relationship in soybean [ Glycine max (L.) Merr., 2n = 40] is not yet established. However, primary trisomics provide an invaluable cytogenetic tool to associate genes and linkage groups to specific chromosomes. We have assigned 11 MLGs to soybean chromosomes by using primary trisomics (2 x + 1 = 41) and SSR markers. Primary trisomics were hybridized with Glycine soja Sieb. and Zucc. (2n = 40) in the greenhouse, F(1) plants with 2n = 40 and 41 were identified cytologically and 41 chromosome plants were selfed. A deviation from the 1:2:1 ratio in the F(2) population suggests a marker is associated with a chromosome. Of the possible 220 combinations involving 20 MLGs and 11 primary trisomics, 151 combinations were examined. The relationships between soybean chromosomes and MLGs are: 1 = D1a+q, 3 = N, 5 = A1, 8 = A2, 9 = K, 13 = F, 14 = C1, 17 = D2, 18 = G, 19 = L and 20 = I. This study sets the stage to establish relationship between nine remaining MLGs with the other genetically unidentified nine primary trisomics. The association of CLGs with the soybean chromosomes will be discussed.

A SNP-Based Genetic Linkage Map of Soybean Using the SoyS - NP6K Illumina Infinium BeadChip Genotyping Array

“…The remaining 107 SNPs were not linked and so were excluded from the maps or linkage groups. The LGs were numbered (1 to 20) based on the assigned chromosome numbers of soybean (Zou et al, 2003). The LOD score of the markers/loci ranged from 4 to 10.…”

“…has 20 chromosomes (2n = 40) and 20 linkage groups (LGs) assigned to them (Zou et al, 2003). To cover the whole soybean genome for the purpose of genome-wide analysis, a large number of molecular markers are imperative (Song et al, 2013).…”

Meiosis-Driven Genome Variation in Plants

“…A set of soybean primary trisomics (2n = 41) were developed from these aneuploid lines [133]. They have been recently used to assign individual genes and molecular linkage groups to specific chromosomes [133][134][135].…”

A Fluorescence in Situ Hybridization System for Karyotyping Soybean

“…(G. max) (2n ¼ 40), was developed using pachytene chromosomes, which were numbered from 1 to 20 on the basis of total chromosome length, arm length ratios, and relative proportions of euchromatin and heterochromatin (Singh and Hymowitz 1988). Primary trisomic lines (2x 1 1 ¼ 41; Xu et al 2000) were used to associate 11 of the 20 MLGs with cytologically numbered chromosomes (Cregan et al 2001;Zou et al 2003). However, this created a problem when the soybean genome sequencing was completed because 9 of the physical chromosomes were unassigned.…”