Ml. Egglestonstott et al., A SINGLE-BASE TRANSVERSION IN THE FLANKING REGION OF AN EQUINE MICROSATELLITE LOCUS AFFECTS AMPLIFICATION OF ONE ALLELE, Animal genetics, 28(6), 1997, pp. 438-440
The equine dinucleotide microsatellite HMS7 is part of a microsatellit
e panel utilized in a parentage verification programme at the Veterina
ry Genetics Laboratory (Davis, California, USA). Apparent non-Mendelia
n inheritance was noted when a Quarter Horse mare was excluded as the
parent of two offspring based on analysis of the HMS7 locus. The mare'
s DNA type qualified her as a parent of the offspring at an additional
20 microsatellite loci. The three animals appeared homozygous for HMS
7 with each possessing an allele different from that of the other two
animals. Polymerase chain reaction primers designed to bind outside th
e published primer-binding sites amplified an additional shared allele
in all three horses, which qualified the mare as the dam of the two o
ffspring. Sequencing of this newly detected allele revealed a C to A t
ransversion in one of the published primer-binding regions. Apparent n
on-Mendelian inheritance at the HMS7 locus has been encountered in an
additional 26 Quarter Horse parentage cases. In all instances, the lac
k of amplification and resultant 'null' allele was shown to be caused
by the same transversion.