Genetic analysis of izoenzymes polymorphisms in silkworm

This work carried out to evaluates the polymorhism in the silkworm of different lineages using the isoenzymes electrophoresis to detect biochemical markers and to investigate the genetics of populations for those lineages. They were used as samples individual extracts of silk glands of second day old larvas of the fifth instar, originating from seven Japanese lineages and eight pure Chinese lineages maintained by the Cocamar-Cooperativa Agroindustrial de Maringa. The isozymes acid phosphatase (ACP), alkaline phosphatase (AKP) and carbonic anhydrase (CA) they were submitted to the electrophoresis in starch gels 14%. The esterases (EST) were analyzed in polyacrylamide gels to 10% and stained with α and β-naphtyl acetate. The total of 21 loci was detected, and 04 (19.05%) they are polymorphic, Est-11, Acp, Akp, Ca. The fixation index ([F.sub.is]) for the analyzed isozymes it was 0.0751, indicating excess of homozygotes. The value of [F.sub.st] (0.6128) it shows that the lineages are well differentiated. The dendrogram obtained with the values of genetic distance didn't separate the Chinese and Japanese lineages analyzed totally. That preliminary evaluation of the lineages of B. mori shows that they present genetic material that it can be used in breeding programs that have the purpose of producing hybrid for silk production. Keywords: silkworm, genetic polymorphism, isoenzymes. Este trabalho teve como objetivo avaliar o polimorfismo em lagartas do bicho-da-seda de diferentes linhagens utilizando a eletroforese de isoenzimas para detectar marcadores bioquimicos e investigar a genetica de populacoes para essas linhagens. Foram utilizados como amostras extratos individuais de glandulas sericigenas de lagartas do segundo dia da quinta idade, de sete linhagens japonesas e oito linhagens chinesas puras mantidas pela Cocamar-Cooperativa Agroindustrial de Maringa. As isozimas fosfatase acida (ACP), fosfatase alcalina (AKP) e anidrase carbonica (CA) foram avaliadas por meio de eletroforese em geis de amido de milho a 14%. As esterases (EST) foram analisadas por meio de eletroforese vertical em geis de poliacrilamida a 10% e coloracao com α e β-naftil acetato. Foram observados 21 locos, dentre os quais quatro (19.05%) sao polimorficos, Est-11, Acp, Akp, Ca. O indice de fixacao ([F.sub.is]) para as isozimas analisadas foi 0.0751, indicando excesso de homozigotos. O valor de [F.sub.st] (0.6128) permite sugerir que as linhagens estao bem diferenciadas. O dendograma obtido