Mapping of simple sequence repeat (SSR) DNA markers in diploid and tetraploid alfalfa |
| |
Authors: | N Diwan J H Bouton G Kochert P B Cregan |
| |
Institution: | (1) Soybean and Alfalfa Research Laboratory, USDA-ARS, Bldg. 006, Rm. 100, BARC-West, Beltsville, MD 20705, USA e-mail: peregan@asrr.arsusda.gov, Present address: N.D. Diwan, The Israeli Gene Bank for Agricultural Crops, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel, US;(2) Department of Agronomy, University of Georgia, Athens, GA 30602, USA, US;(3) Department of Botany University of Georgia, Athens, GA 30602, USA, US |
| |
Abstract: | Cultivated alfalfa (Medicago sativa) is an autotetraploid. However, all three existing alfalfa genetic maps resulted from crosses of diploid alfalfa. The current
study was undertaken to evaluate the use of Simple Sequence Repeat (SSR) DNA markers for mapping in diploid and tetraploid
alfalfa. Ten SSR markers were incorporated into an existing F2 diploid alfalfa RFLP map and also mapped in an F2 tetraploid population. The tetraploid population had two to four alleles in each of the loci examined. The segregation of
these alleles in the tetraploid mapping population generally was clear and easy to interpret. Because of the complexity of
tetrasomic linkage analysis and a lack of computer software to accommodate it, linkage relationships at the tetraploid level
were determined using a single-dose allele (SDA) analysis, where the presence or absence of each allele was scored independently
of the other alleles at the same locus. The SDA diploid map was also constructed to compare mapping using SDA to the standard
co-dominant method. Linkage groups were generally conserved among the tetraploid and the two diploid linkage maps, except
for segments where severe segregation distortion was present. Segregation distortion, which was present in both tetraploid
and diploid populations, probably resulted from inbreeding depression. The ease of analysis together with the abundance of
SSR loci in the alfalfa genome indicated that SSR markers should be a useful tool for mapping tetraploid alfalfa.
Received: 10 September 1999 / Accepted: 11 November 1999 |
| |
Keywords: | Medicago sativa Autotetraploid linkage map Microsatellites SSR Inbreeding depression Single dose allele (SDA) analysis |
本文献已被 SpringerLink 等数据库收录! |
|