PAG-I Plant Genome I Conference

Town & Country Conference Center, San Diego, CA, November, 1992.


PG-I: 42pg1

PARALLEL STUDIES OF GENE AND GENOME ORGANIZATION IN MAIZE AND SORGHUM.

Jeff Bennetzen 1, Patricia Springer l, Admasu Melake- Berhan 1, Kathrin Schrick 1, Chang-Nong Liu 1, Scot Hulbert 1 and Keith Edwards 2, 1 Department of Biological Sciences, Purdue University, West Lafayette, IN 47907 and 2 Plant Biotechnology Section, I.C.I. Seeds, Jealotts Hill Research Station, Bracknell, Berkshire RG12 6EY, UK.


Maize and sorghum are closely related members of the tribe Andropogonae, and each has 10 pairs of chromosomes per diploid nucleus. Sorghum, however, has an approximately four fold smaller genome. We have found that single copy sequences in these two species generally cross-hybridize very efficiently, and can be used to generate parallel restriction fragment length polymorphism (RFLP) maps. The results of such studies indicate that most low copy number sequences from maize are represented at similar copy numbers in sorghum, and that the two genomes are largely colinear. Several genomic rearrangements do differentiate these species, however. We have begun detailed molecular and genetic analyses of the DNA near the Adh1 locus of maize, and its homeologue in sorghum. We have investigated the stability and organization of different classes of DNA in 280 kb of contiguous sequences surrounding maize Adh1, which we have cloned as yeast artificial chromosomes (YACs). We have analyzed the homeologous region in sorghum on a series of overlapping cosmid clones. The results of these studies, indicating unexpected patterns and differences in the organization of these two genomes, will be presented.


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