ABSTRACT
In the case of two mismatches observed in alleged parent-offspring pairs, there is doubt as to whether there is an exclusion of the putative parent or the existence of two mutations. Here, we report on four cases with two mismatches in paternal/maternal duos based on capillary electrophoresis (CE) results. The analyzed next generation sequencing (NGS) results were compared with 20 autosomal STRs derived from previous CE-based analysis. In summary, the NGS samples used offered comprehensive information of different types of markers that can improve resolutions for paternal/maternal duos analysis.
Subject(s)
High-Throughput Nucleotide Sequencing , Microsatellite Repeats , Mothers , Paternity , Chromosomes, Human, X , Electrophoresis, Capillary , Female , Genetic Markers , Humans , Male , Mutation , Polymerase Chain ReactionABSTRACT
Short tandem repeat (STR) multiplexes with the amelogenin (AMEL) gene as a gender marker have been used as a routine tool of forensic DNA analysis. It has been reported that AMEL-based gender detection could misidentify a known male as a female due to the dropout of amelogenin Y (AMELY) allele. Other gender markers, such as Y-chromosomal short tandem repeat (Y-STR), may be a substitution of AMEL and help the sex determination. In current study, employing AmpFlSTR® Sinofiler and AmpFlSTR® Y-filer™ PCR Amplification kit, 18 AMELY-negative males were identified. Accordingly, the incidence of the AMELY dropout was 0.227 (18/79,304) in Chinese population. Sequencing of AMELY allele and analyzing of azoospermia factors region suggested that 3 out of 18 misidentifications were induced by mutations in the primer-binding region of the AMELY, while other 15 sex misidentifications were results of Y chromosome microdeletions with variant lengths. Moreover, variant combination patterns of AMELY dropout and Y-STRs deletions were also observed. Our data suggested that Y-STR locus dropout may indicate more problems, especially in the mixed sample's interpretation. Results of haplogroup prediction showed that seven AMELY dropouts combined with variant Y-STR deletions can be classified as the J2 subdivision, suggesting that some of these Y chromosomes might descend from a common ancestor.
Subject(s)
Alleles , Amelogenin/genetics , Genotype , Microsatellite Repeats/genetics , Sex Chromosome Disorders of Sex Development/genetics , Asian People/genetics , Azoospermia/genetics , China , Chromosome Deletion , Chromosomes, Human, Y/genetics , Cross-Cultural Comparison , DNA Mutational Analysis , Forensic Genetics/methods , Founder Effect , Gene Frequency/genetics , Genetics, Population , Haplotypes , Humans , Infertility, Male , Male , Multiplex Polymerase Chain Reaction , Nucleic Acid Amplification Techniques , Sex Chromosome Aberrations , Sex Determination Processes/geneticsABSTRACT
The male-specific Y-chromosomal short tandem repeat (STR) is a useful tool in forensic casework. The Y haplotype comprised of 16 loci, which is amplified simultaneously by AmpFlSTR(®) Yfiler(TM) PCR kit and provides strong exculpatory evidence in individual identification. We reported a rare Y-STR profile with a null allele at the DYS448 locus and an off-ladder allele at the DYS456 locus, when genotyping material from a vaginal swab in an alleged rape case. Sequence analysis revealed that the DYS448 null allele was a true type of null allele because of a total deletion of 11 upstream repeats and 9bp of the N(42) region, and there were numerous primer binding site mutations as well. The amplicon of the DYS456 locus was a small 92-bp fragment that was off-ladder, and sequencing analysis showed that there were only 10 repeats (AGAT)(10). This Y chromosome haplotype that was comprised of two variations provided helpful evidence for personal identification.
Subject(s)
Chromosomes, Human, Y , Haplotypes , Microsatellite Repeats , Mutation , Alleles , Base Sequence , DNA Fingerprinting , Electrophoresis , Female , Humans , Male , Polymerase Chain Reaction , Sequence Analysis, DNAABSTRACT
Low template DNA (LTDNA) has been widely applied in the field of forensic science in recent years. However, the application of low copy number(LCN) analysis is still controversial in certain forensic. This paper focus on the definition of LCN and LTDNA, casework because of its inherent limiting factors. the validity and application of LCN in forensic science, methods of typing, quality control, replicate analysis, detection thresholds and then reviews the latest development of LCN in forensic science.
