Proceedings of the XLVI Italian
Society of Agricultural Genetics - SIGA Annual Congress
Giardini
Naxos, Italy - 18/21 September, 2002
ISBN 88-900622-3-1
Poster
Abstract - 4.20
structure
of Linkage disequilibrium in barley landrace populations and commercial
varieties
Rau D.*, Attene G.*, Rodriguez M.*, Angioi S.*,
Ferradini N.**, Rossi M.**, D'Amico T.**, PAPA R.**
*)
Dipartimento di Scienze Agronomiche e Genetica Vegetale Agraria,
Università degli Studi di Sassari, Sassari, Italy
**)
Dipartimento di Biotecnologie Agrarie ed Ambientali, Università degli
Studi di Ancona, Ancona, Italy
Hordeum
vulgare, linkage disequilibrium, population structure, SSR, ISSR
Linkage disequilibrium (LD) is the nonrandom association of alleles at
two (or more) loci. The extent of LD in natural and domesticated populations is
mainly related to the effective recombination rate, the mating system and the
population size. LD is promoted by drift, hitchhiking and epistatic selection,
i t has become the matter of intensive studies in human genetics with the
objective of identifying genes for genetic diseases and, more recently, in crop
species such as Zea mays. Population subdivision
and population admixture are also influencing the pattern of LD and should be
carefully taken into account in data interpretation.
In autogamous species
few data are available and it is still not clear the extent to which this
approach could be suitable. Indeed, the low effective recombination rate may
cause high LD over too large portion of the genome making ineffective any study
of association between neutral and selected loci.
In our
study we analysed the structure of LD in 10 barley landrace populations (30
individuals per population) and 60 commercial varieties using 10 mapped SSR and
20 ISSR loci. A very low LD was found in landrace populations in comparison
whith what expected in strictly autogamous species suggesting that these
material could be very useful for association genetics studies in barley.