Population haplotype analysis and evolutionary relations of the COL2A1 gene.

We have determined the allele frequencies and pairwise linkage disequilibria of restriction fragment length polymorphisms (RFLPs) distributed over the entire COL2A1 gene (spanning 23.6 kb) in a population of unrelated Dutch Caucasians. Pairwise linkage disequilibrium analysis of RFLP sites between exon 5B and 51 indicated a high degree of partly positive (the rare alleles of both loci are associated) and partly negative (the rare allele is associated with the common allele) linkage disequilibrium. The high degree of linkage disequilibrium enabled the assignment of 13 out of 128 possible haplotypes with 7 RFLPs. An evolutionary tree of these haplotypes was derived using a minimum spanning tree approach, indicating at least two ancestral haplotypes. Our data indicate that disease related population studies involving the COL2A1 gene should include a minimum of 4 RFLPs (D9, A9, H33, P51) to obtain 98% of possible haplotypes occurring.