Objective: To investigate polymorphisms in the coding exons and their splicing areas of caspase10 gene (CASP10) in Chinese of Han nationality.
Methods: Polymerase chain reaction (PCR), denaturing high-performance liquid chromatography (DHPLC), direct sequencing and clonal sequencing were used to analyze the exon 9 and its flanking sequences.
Results: In 70 blood samples of Chinese subjects researched the known single nucleotide polymorphisms (SNPs) in the exon 9 of CASP10 gene published in dbSNP of NCBI were not identified. We found a short sequence with more than ten continuous and repeated T nucleotides within the intron 8 near the exon 9 and the length of repeated sequence nucleotides T was different in samples. Clonal sequencing analysis indicated that it was a microsatellite of single nucleotide-repeated sequence. The recurrence and specificity of same result was further confirmed by PCR with high fidelity polymerase and sequencing. Furthermore all of 70 blood samples detected by DHPLC showed heterozygous profiles. We named it as IVS8-13(T)n temperately.
Conclusion: Our research suggested that the site be a microsatellite of single nucleotide-repeated sequence. Meanwhile, our data further showed that it was quite different from that by querying SNP database of non-Chinese population in NCBI, in the same region a SNP of type of insertion deletion existed. It could be inferred that the difference between the populations might be associated with the genetic characteristics of ethnics. The significance of the microsatellite in CASP10 gene in Chinese of Han nationality remains to be elucidated.