Rose, Sara B. , Olfelt, Joel P. , Forsline, Philip L. , Luby, James J. .
Genetic diversity within and among Malus pumila populations of Central Asia.
Malus pumila, the currently accepted ancestor of domesticated apples, is believed to have originated in the apple forests of the Tien Shan mountain range in Central Asia. The forests stretch along the borders of Kazakhstan, Tajikistan, Kyrgyzstan, and China in the form of populations isolated by mountain valleys and desert areas. The morphological variability within and among these populations is not found in any other geographical region, and is so high that some have suggested that they contain multiple species. Currently, the area is under pressure from human activities, with an estimated loss of as much as 90% of the apple forests. If the populations were isolated during the formation of the Tien Shan mountain range 8-10 million years ago, then genetic differences among populations should be significant. However, this mountain range is along the Silk Road, and caravan activities may have effected gene flow over the last few thousand years. We have used 6 primer pairs to generate microsatellite markers from DNA extracted from 124 individuals sampled during a 1996 expedition to Kazakhstan. The individuals are from 6 populations, and sample sizes for the populations range from 16 to 29. The primer pairs have produced a range of 8 to 23 markers per primer pair, giving a total of 99 markers. Nine of these are unique to single populations, 4 occurring in one population, while 47 of the markers occur in all six populations. Distance analyses using NTSys software demonstrate a general correlation between taxonomic distance and geographic distance. The presence of the unique markers suggests that some populations have been at least partly isolated, but the high level of shared markers suggests important levels of gene flow among populations.
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1 - Northeastern Illinois University, Department of Biology, 5500 N. St Louis, Chicago, Illinois, 60625
2 - Northeastern Illinois University, Biology, 5500 North St. Louis Avenue, Chicago, Illinois, 60625, USA
3 - Cornell University, usda-pgru, 630 W. North St., Geneva, New York, 14456
4 - University of Minnesota, Department of Horticulture Science, 342 Alderman Hall, 1970 Folwell Avenue, St. Paul, Minnesota, 55413
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM