FRAGARIA STRAWBERRY

Strawberry MYB10 is the main factor responsible for the pigmentation in the skin and flesh of the berries. Notably, it contains a string of polyadenine-thymine (polyTA) in the second intron. Interestingly, the three taxa—Fragaria moschata, Fragaria vesca, and the cultivated plant Fragaria x ananassa—each have polyTA strings of different lengths. However, they all share the same exon and intron information, differing only in the lengths of their polyTA strings. See the picture below for reference.

Fragaria x anannassa STR polyTA length distribution in the first intron of MYB10 

Fragaria moschata STR polyTA length distribution in the first intron of MYB10 (EU155163.1)

The asymmetric distribution of polyTA in short tandem repeats (STRs) as somatic mutations suggests that STRs tend to shorten. The somatic mutation rate is notably high (p > .65). Use BLAST EU155163   against ERX12134001 to gain an overview.

You achieve better results when you omit one TA repeat from the STR.

The result along the STR will resemble what is depicted above. 

Fragaria vesca  EU155163.1   ERX12326309

The unequal distribution of polyTA in short tandem repeats (STRs) as somatic mutations indicates a tendency for STRs to lengthen.