#tetranucleotiderepeat

Abstract To obtain information of Periplaneta americana, we analyzed the distribution characteristics of microsatellite sequences in the P. americana transcriptome (229 MB) by using MSDBv2.4. The total number of perfect microsatellite sequences was 38 082 and covered about 0.3% of P. americana transcriptome. The cumulative length of microsatellites was 618 138 bp, and the density of microsatellites was 2978.54 bp/Mb. In the different repeat types of the microsatellites, the number of the mononucleotide repeats was 20 002 (accounting for 52.52%), which obviously was the most abundant type. While the trinucleotide, tetranucleotide, dinucleotide, pentanucleotide and hexanucleotide repeats accounted for 24.51, 12.97, 8.13, 1.61 and 0.26%, respectively. The kind of different repeat copy categories in each repeat type was also quite different, such as the A in mononucleotide repeat type, the AG in dinucleotide, the AAT in trinucleotide, AAAT in tetranucleotide, the AAGAA in pentanucleotide, and the CAGTAG in hexanucleotide were the most of each category. The A, T, AC, AG, AT, GT, AAG, AAT, ATC, ATG, ATT, CTT, AAAG and AAAT were the dominant repeat copy categories, the total number of all these types was 29 933, accounting for 78.6% in the total number of microsatellite sequences. These results based on a foundation for developing high polymorphic microsatellites to research the functional genomics, population genetic structure and genetic diversity of P. americana.