Isolation and characterization of chromosome‐specific DNA sequences from a chromosome arm genomic library of common wheat

Abstract

Isolation, physical mapping and polymorphism of chromosome‐specific DNA sequences in wheat are reported. Following the microdissection of the long arm of chromosome 5B (5BL) of common wheat, its DNA was amplified by degenerate oligonucleotide‐primed PCR and directly cloned into plasmid vectors. Characterization of the chromosome arm library showed that ∼55% of the inserts are of low‐copy nature. Southern analysis using aneuploid lines of common wheat revealed that five of 11 low‐copy inserts analyzed map to chromosome arm 5BL; four of these are 5BL‐specific. By deletion mapping, the 5BL‐specific sequences were located to sub‐ chromosome arm regions. Based on the hybridization patterns of three 5BL‐specific sequences to DNA from a diverse collection of goat‐grass (Aegilops) and wheat (Triticum) species, it was concluded that these sequences emerged at different times in the course of evolution of this group of plant species.