Analysis of the Yp11.2 Deletion Region of Phenotypically Normal Males with an AMELY-Null Allele in the Chinese Han Population.

Aim: The amelogenin gene is a widely used gender marker for forensic DNA profiling. Males who have the amelogenin Y (AMELY) allele deletion can be mistakenly identified as females if genotyping is performed only on the amelogenin gene. The aim of this study was to investigate the frequency of the AMELY allele deletion in the Chinese Han population and analyze the possible genetic variation on the Y chromosome. Materials and

Methods

The amelogenin gene of 12,735 unrelated males from the Chinese Han population were genotyped using common forensic short tandem repeat (STR) kits. The AMELY allele deletion was verified by redesigned primers and sequencing. Eighteen Y-specific sequence tagged sites (STSs) on the Yp11.2 region were selected to delineate the deletion breakpoints on the Y chromosome.

Results

Three males were confirmed to have no AMELY allele. The frequency rate of the AMELY-null allele was 0.236% (3/12,735) in the Chinese Han population of Central China; 2.73 Mb of sequence on the Y chromosome were absent in all the AMELY-negative samples. The deleted region was mapped using SRY, AMELY, 5 Y-STRs, and 18 STSs, which belong to the class I deleted pattern. The three unrelated males shared the same Y-STR haplotype with four males from other Chinese populations, all of whom have the AMELY-null allele. The haplogroup of these males was identified as the O3 haplogroup.

Conclusion

The AMELY allele deletion in the Chinese population was accompanied by the deletion of the Y-STR loci on the Yp11.2 region. Therefore, another Y-specific marker should be tested simultaneously when unknown samples are examined as part of a criminal investigation.