Z38845 is a G to A mutation at position 7483249. This mutation is on the short arm of the Y chromosome in the IR1 region. There are 3 similar regions on the long arm of the Y chromosome and as such it does not show up cleanly in NGS tests if it shows up at all. NGS BAM files will usually show a mixture of G and A reads at this position. Paired end reads can pick up a difference between the regions and suggest that the mutation really is at 7483249.
A red background is used for men whose data has not yet been fully analyzed. His position on the tree is not yet final, and will in general be downstream of the current position. He may not be positive for all the SNPs/INDELs in the block he descends from.
Men whose NGS data have been fully analyzed are indicated with a grey background color.
Those men with a grey background and a pink bar to their left have been finalized, but haven't gone through as much scrutinity as earlier kits have. In particular, no search has been made for recurrent SNPs or other unusual mutations. For the vast majority of kits, this has no effect at all, but I will review them as necessary in the future.
Mutations written with a red background fall within a region of the Y chromosome, such as the palindromic region, which has left the position of the mutation ambiguous. The true mutation may be at the indicated position, or at any one of a number of alternate positions.