RRC ID 551
Author Prasad MD, Muthulakshmi M, Madhu M, Archak S, Mita K, Nagaraju J.
Title Survey and analysis of microsatellites in the silkworm, Bombyx mori: frequency, distribution, mutations, marker potential and their conservation in heterologous species.
Journal Genetics
Abstract 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.
Volume 169(1)
Pages 197-214
Published 2005-1-1
DOI 10.1534/genetics.104.031005
PII genetics.104.031005
PMID 15371363
PMC PMC1448858
MeSH Animals Bombyx / classification Bombyx / genetics* Chromosomes, Artificial, Bacterial Computational Biology Conserved Sequence Expressed Sequence Tags Genes, Insect* Genetic Markers / genetics* Microsatellite Repeats / genetics* Mutation / genetics* Polymorphism, Genetic* Sex Chromosomes / genetics
IF 4.015
Times Cited 58
Silkworms Antheraea pernyi Antheraea yamamai Samia cynthia ricini