Abnormal detection of Y-STR alleles at DYS385 from female DNA in forensic casework and interchromosomal insertional translocation of P4 palindrome (HSFY/DYS385) from AZFb region. (March 2019)

• Record Type: Journal Article
• Authors: Kim, Soon Hee; Lee, Jin Myeong; Hyun, Young Se; Choi, Dong Ho
• Is Part Of: Legal medicine. Volume 37(2019)
• Page Start: 95
• Page End: 102
• Publication Date: 2019-03
• Subjects: DYS385 -- Y chromosome -- AZFb -- HSFY -- P4 palindrome -- Insertional translocation; Medical jurisprudence -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Medical jurisprudence; Periodicals; 614.1
• DOI: 10.1016/j.legalmed.2019.02.002
• Languages: English
• ISSNs: 1344-6223

Abstract

Highlights: Unusual STR genotypes can affect interpretation of results in forensic genetics. Y-STR alleles were detected at the DYS385 and DYS460 loci in a female sample. Y chromosome segment including HSFY1 and HSFY2 was inserted into female DNA. Abstract: The unknown origin of DNA samples derived from crime scenes generates a considerable amount of uncertainty, as do unexpected short tandem repeat (STR) results caused by sample mix-ups, contamination, medical interventions, and transgender individuals (broad meaning). Genetic abnormalities such as somatic/germline mutations, mosaicism or chimerism, sex reversal cases, aneuploidies, and chromosomal structural rearrangements are also possible causes of such results. The evidence offered by the present study suggested that additional DYS385 alleles, as seen in mixed stain samples and in the potentially single-source DNA profile of a female, originated from the female DNA source only. For the case reported here, we propose an interchromosomal insertion hypothesis, in which a 768-kb segment including the P4 palindrome of the azoospermia factor (AZFb) region was deleted from the Y chromosome and inserted into the X chromosome or an autosome during male meiosis. Y-SNP data points from the AccuID platform and in-house PCR assays narrowed down the expected length of the target region. Bioinformatics analysis followed by whole genome amplification and whole genome sequencing showed that a 529-kb segment including the P4 palindrome ( HSFY /DYS385)/DYS460 region from the female sample mapped to the Y reference sequence (GRCh37). To our knowledge, the interchromosomal insertional translocation event was identified as an unknown type of genomic rearrangement in the forensic genetic field.