Survey and analysis of microsatellites in the silkworm, Bombyx mori

Dharma Prasad, M. ; Muthulakshmi, M. ; Madhu, M. ; Archak, Sunil ; Mita, K. ; Nagaraju, J. (2005) Survey and analysis of microsatellites in the silkworm, Bombyx mori Genetics, 169 . pp. 197-214. ISSN 0016-6731

PDF - Publisher Version

Official URL:

Related URL:


We studied microsatellite frequency and distribution in 21.76-Mb random genomic sequences, 0.67-Mb BAC sequences from the Z chromosome, and 6.3-Mb EST sequences of Bombyx mori. We mined microsatellites of ≥15 bases of mononucleotide repeats and ≥5 repeat units of other classes of repeats. We estimated that microsatellites account for 0.31% of the genome of B. mori. Microsatellite tracts of A, AT, and ATT were the most abundant whereas their number drastically decreased as the length of the repeat motif increased. In general, tri- and hexanucleotide repeats were overrepresented in the transcribed sequences except TAA, GTA, and TGA, which were in excess in genomic sequences. The Z chromosome sequences contained shorter repeat types than the rest of the chromosomes in addition to a higher abundance of AT-rich repeats. Our results showed that base composition of the flanking sequence has an influence on the origin and evolution of microsatellites. Transitions/transversions were high in microsatellites of ESTs, whereas the genomic sequence had an equal number of substitutions and indels. The average heterozygosity value for 23 polymorphic microsatellite loci surveyed in 13 diverse silkmoth strains having 2-14 alleles was 0.54. Only 36 (18.2%) of 198 microsatellite loci were polymorphic between the two divergent silkworm populations and 10 (5%) loci revealed null alleles. The microsatellite map generated using these polymorphic markers resulted in 8 linkage groups. B. mori microsatellite loci were the most conserved in its immediate ancestor, B. mandarina, followed by the wild saturniid silkmoth, Antheraea assama.

Item Type:Article
Source:Copyright of this article belongs to Genetics Society of America.
ID Code:24301
Deposited On:29 Nov 2010 09:15
Last Modified:17 May 2016 08:01

Repository Staff Only: item control page