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Comparative genome mapping of Sorghum and maize
1Department of Botany and Plant Sciences, University of California, Riverside 92521.
Genetics
|December 1, 1992
Summary
Maize DNA probes reveal conserved linkage groups between maize and sorghum genomes, indicating shared evolutionary history. Genome divergence primarily resulted from duplications and inversions, not large translocations.
Area of Science:
- Genetics
- Genomics
- Evolutionary Biology
Background:
- Maize (Zea mays) and sorghum (Sorghum bicolor) are important cereal crops with related genomes.
- Understanding genome evolution requires comparative mapping studies.
Purpose of the Study:
- To construct a genetic linkage map of sorghum using maize DNA probes.
- To infer the evolutionary processes that have shaped the divergence of maize and sorghum genomes.
Main Methods:
- Developed a sorghum linkage map using 85 maize low copy number nuclear DNA probes and seven isozyme loci in an F2 population.
- Analyzed conserved linkage groups, recombination rates, and locus duplication proportions between maize and sorghum.
Main Results:
- Defined 13 sorghum linkage groups, revealing conserved synteny with maize chromosomes.
- Found equivalent recombination rates in conserved linkage groups.
- Observed a higher proportion of duplicated loci in maize compared to sorghum.
- Identified nine inversions or intrachromosomal translocations within shared linkage groups.
Conclusions:
- Maize and sorghum genomes share conserved linkage groups, supporting an ancient polyploid origin.
- Genome divergence is attributed to duplications and intrachromosomal rearrangements.
- Comparative genomics provides insights into cereal crop evolution.