Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: DUPLICATE GENETIC FACTORS AND SOYBEAN GENOME
ORGANIZATION
DUPLICATE GENETIC FACTORS AND SOYBEAN GENOME
ORGANIZATION
Randy C. Shoemaker 1,2, E. Charles Brummer 1, Eberson S. Calvo 3,
and Kayla M. Polzin 1. 1 Dept. of Agronomy, 2 USDA-ARS-FCR, and
3 Dept. of Zoology/Genetics, Iowa State University, Ames, IA
50011.
Soybean (Glycine max (L.) Merr.) is an ancient tetraploid with
a highly diploidized genome. About 15% of the random genomic
clones used in the construction of the USDA/ISU public RFLP map
have mapped duplicate independent loci using a single enzyme.
However, the vast majority of the probes detect multiple (3-9)
bands on an autoradiograph. Our results suggest that each band
has the potential to correlate to a genomic locus. Intensive
mapping efforts using multiple enzymes and alternative mapping
populations have identified a large number of duplicate loci.
Linked duplicate loci can be identified which delineate apparent
segmental duplications. Although some duplicate regions appear
to be randomly dispersed, others are clearly tandemly repeated.
The arrangement of these segments throughout the genome and the
lack of cross-hybridization outside of "core" regions within
segments indicate that the soybean genome has undergone
tremendous internal reorganization through rearrangement and
sequence divergence, with many regions being duplicated multiple
times. The soybean demonstrates many examples of qualitative
traits controlled by two or more duplicate loci. This suggests
the potential for duplicate factors to play a role in expression
of complex quantitative traits. We are attempting to correlate
data from QTL mapping studies with what we are learning about the
structure and organization of the soybean genome. This
information may provide insight into the expression and
regulation of complex traits in soybean.
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