PAG-I Plant Genome I Conference

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


PG-I: LINKAGE MAP OF SLASH PINE BASED ON MEGAGAMETIC DNA

LINKAGE MAP OF SLASH PINE BASED ON MEGAGAMETIC DNA.

J.P. van Buijtenen*, X. Kong*, E. Funkhouser*, W.L. Nance**, C.D. Nelson**, L.S. Nelson**, G.N. Johnson**. * Texas Agricultural Experiment Station, Texas A&M University, College Station, TX 77843 ** Forestry Sciences Laboratory, USDA Forest Service, Gulfport, MS 39505.


DNA from sixty-four megagametophytes of slash pine D4PC40 was extracted using a CTAB extraction procedure. The DNA was used to develop a genetic map using the RAPD marker technique. Since each megagametophyte is equivalent to a single haploid gamete, this technique works extremely well, since the absence or presence of each marker can be observed directly. The RAPD reactions were performed using the automated facilities of the USFS laboratory at Gulfport, MS, which made it possible to run 1536 PCR reactions per day. A total of 384 primers were screened of which 94 were used for mapping purpose. Two primers were run in duplicate for a total of 96. The PCR reactions resulted in 209 scoreable polymorphic bands of which 24 were eliminated, because the segregation ratio deviated significantly from 1:1 (a = .05). The remaining 185 loci formed 19 linkage groups of three or more loci and four pairs. One locus was not linked to any others. The resulting map covered 1776 cM or about 59 percent of the estimated 3000 cM genome. This is less than expected and probably caused by the tendency for many of the loci to cluster into fairly tightly linked groups.


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