Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 65pg1
CO-DOMINANT INHERITANCE OF SIMPLE SEQUENCE REPEAT (SSR)
GENETIC MARKERS IN SOYBEAN AND THEIR LINKAGE RELATIONSHIPS.
Mahinur S. Akkaya, Perry B. Cregan, Soybean and Alfalfa Research
Lab, USDA, ARS, Beltsville, MD 20705 and James E. Specht,
Department of Agronomy, University of Nebraska, Lincoln, NE
68583.
The presence of length polymorphism of Simple Sequence
Repeat (SSR) DNA was demonstrated recently in our laboratory for
the first time in plants. The length polymorphisms of SSRs are
a result of variation in the number (n) of repeat units in SSR
sequences such as (AT)n and (ATT)n. A search of soybean DNA
sequences in GenBank revealed four loci containing n = 14 to 24
AT SSRs and one ATT SSR. PCR amplification of these loci using a
variety of homozygous soybean genotypes in the presence of
radiolabelled nucleotide and subsequent electrophoresis of these
products resulted in high levels of SSR length polymorphism.
Co-dominant I segregation of SSR markers with the soybean crosses
of 'Williams' x 'Amsoy' and 'Jackson' x Williams was
demonstrated. We have attempted to map three SSR markers,
SoyABAB, SoyHSP176, and SoyPRP1, in a cross of 'Clark' x
'Harosoy' in which a number of morphological, isozyme, and RFLP
markers have already been mapped. We were successful in finding
linkage of the SoyHSP176 marker to one isozyme and one RFLP
marker. The SoyPRP1 SSR marker was also linked to another RFLP
marker.
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