Figure 6.

Evolutionary Network of all 4q and 10q Sequence Haplotypes

A median-joining network based on all distinct 4q and 10q haplotype sequences shown in Figure 4. In order to reconstruct the evolutionary root of the network, we included the orthologous D4Z4 region present on chimpanzee chromosome 3 (chimp). All haplotypes could be grouped in six distinct clusters: (a) and (b) (representing major group 1, left of chimp) and (c), (d), (e), and (f) (representing major group 2, positioned right of chimp). The major difference between haplotypes from clusters (a) and (b) is the distal variation, A and B, respectively. The introduction of the distal B variation between clusters (a) and (b) is indicated with an arrow. Cluster (c) is the only subgroup in major group 2 that contains haplotypes with the distal B variation. Cluster e consists of haplotypes that carry hybrid D4Z4 repeat arrays. This network clearly indicates that only three transfers from 4 to 10 (indicated with a T and a black arrow) and a single transfer of the distal B variation within chromosome 4 (indicated with a gray dotted arrow between clusters b and c) are sufficient to explain all major groups of variants.