title: Allelic Variability in the Intronic Region of the Fibroin Heavy-Chain Gene in Silkworm Bombyx mori L. Strains of Brazilian Germplasm Bank.
abstract: The domesticated silkworm Bombyx mori L. is currently found only in germplasm banks. Therefore, characterization and conservation of this genetic resource is crucial. Based on previous studies that revealed nucleotide differences in silkworm strains, the intron of the fibroin heavy chain gene (H-fib) can be used for molecular silkworm characterization. The H-fib gene has two exons and a unique intron, and encodes the principal component of the silk fiber, the fibroin heavy chain. Therefore, this study aimed to identify the genetic variability of the unique intron of H-fib gene of 20 silkworm strains maintained at the Universidade Estadual de Maringá Brazilian Germplasm Bank (UBGB) by conformation-sensitive gel electrophoresis (CSGE) and nucleotide sequencing. Genomic DNA extracted from silkworm moths was PCR amplified. CSGE revealed that most of the analyzed silkworm strains had only homoduplex molecules. However, DNA from the Japanese strains B106, B82, and M12-2 had two extra DNA fragments produced by heteroduplex molecules, revealing variation between alleles. Sequencing of the H-fib intron was used to confirm the variation previously detected by CSGE and detected a significant polymorphism characterized by a 17-base pair (bp) deletion, a 2-bp insertion, and eight nucleotide substitutions. Although genetic and allelic variability was detected in some silkworm strains, the intron of the H-fib gene revealed not to be the best molecular marker for the characterization of B. mori strains from UBGB.
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil. thabignotto@yahoo.com.br.
authors.forename: T S
authors.initials: TS
authors.lastname: Bignotto
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil.
authors.forename: R E F
authors.initials: RE
authors.lastname: Munhoz
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil.
authors.forename: N C
authors.initials: NC
authors.lastname: Pereira
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil.
authors.forename: R
authors.initials: R
authors.lastname: Bespalhuk
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil.
authors.forename: C R N
authors.initials: CR
authors.lastname: Saez
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil.
authors.forename: V A
authors.initials: VA
authors.lastname: Fassina
authors.affiliation: Depto de Biotecnologia, Biologia Celular e Genética, Univ Estadual de Maringá, Av. Colombo, 5790, Bloco B36, 87020-900, Maringá, PR, Brasil.
authors.forename: M A
authors.initials: MA
authors.lastname: Fernandez
mesh_terms: D000483:Alleles; D000818:Animals; D012831:Bombyx / Q000235:genetics*; D001938:Brazil; D005349:Fibroins; D017344:Genes, Insect; D007438:Introns; D011110:Polymorphism, Genetic
chemical_list: D005349:Fibroins
keywords: Allelic variability; H-fibroin; conformation-sensitive gel electrophoresis; heteroduplex; silkworm germplasm bank