Allelic variation in the contiguous loci encoding XXXX ALS5, @entity7104 .

@entity2655 @entity7104 @entity70925 @entity5132
The @entity2655 gene family of @entity5132 consists of eight genes ( @entity7104 to ALS7 and @entity70925 ) that encode cell-wall glycoproteins involved in adhesion to host surfaces. Considerable allelic sequence variability has been documented for regions of @entity2655 genes encoding repeated sequences. Although regions of @entity2655 genes encoding non-repeated sequences tend to be more conserved, some sequence divergence has been noted, particularly for alleles of ALS5. Data from the @entity5132 genome sequencing project provided the first indication that strain SC5314 encoded two divergent @entity70925 -like sequences and that three of the @entity2655 genes (ALS5, @entity7104 ) were contiguous on chromosome 6. Data from PCR analysis and construction of both single and double deletion mutants indicated that the divergent sequences were alleles of @entity70925 , and located downstream of ALS5 and @entity7104 . Sequences within the 5' domain of @entity70925 -1 and @entity70925 -2 varied by 11 %. Within the 3' domain of each allele, extra nucleotides were present in two regions of @entity70925 -2, designated Variable Block 1 (VB1) and Variable Block 2 (VB2). Analysis of strains from the five major @entity5132 genetic clades showed that both @entity70925 alleles are widespread among these strains, that the sequences of @entity70925 -1 and @entity70925 -2 are conserved among diverse strains and that recombinant @entity70925 alleles have been generated during @entity5132 evolution. Phylogenetic analysis showed that, although divergent in sequence, @entity70925 alleles are more similar to each other than to any other @entity2655 genes. The degree of sequence divergence for @entity70925 greatly exceeds that observed previously for other @entity2655 genes and may result in functional differences for the proteins encoded by the two alleles.
