An expressed sequence tag SSR map of tetraploid alfalfa (Medicago sativa L.)

M K Sledge, I M Ray, G Jiang
TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik 2005, 111 (5): 980-92
A genetic map constructed from a population segregating for a trait of interest is required for QTL identification. The goal of this study was to construct a molecular map of tetraploid alfalfa (Medicago sativa.) using simple sequence repeat (SSR) markers derived primarily from expressed sequence tags (ESTs) and bacterial artificial chromosome (BAC) inserts of M. truncatula. This map will be used for the identification of drought tolerance QTL in alfalfa. Two first generation backcross populations were constructed from a cross between a water-use efficient, M. sativa subsp. falcata genotype and a low water-use efficient M. sativa subsp. sativa genotype. The two parents and their F(1) were screened with 1,680 primer pairs designed to amplify SSRs, and 605 single dose alleles (SDAs) were amplified. In the F(1), 351 SDAs from 256 loci were mapped to 41 linkage groups. SDAs not inherited by the F(1), but transmitted through the recurrent parents and segregating in the backcross populations, were mapped to 43 linkage groups, and 44 of these loci were incorporated into the composite maps. Homologous linkage groups were joined to form eight composite linkage groups representing the eight chromosomes of M. sativa. The composite maps consist of eight composite linkage groups with 243 SDAs from M. truncatula EST sequences, 38 SDAs from M. truncatula BAC clone sequences, and five SDAs from alfalfa genomic SSRs. The total composite map length is 624 cM, with average marker density per composite linkage group ranging from 1.5 to 4.4 cM, and an overall average density of 2.2 cM. Segregation distortion was 10%, and distorted loci tended to cluster on individual homologues of several linkage groups.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"