Organization of the chorion genes of Bombyx mori, a multigene family. I. Evidence for linkage to chromosome 2.
The chorion genes of silkmoths comprise a multigene family that codes for 50 or more highly specialized structural proteins found in the eggshell. A detailed study of the chromosomal organization of these genes was initiated, using inbred stocks of Bombyx mori as a source of electrophoretic variants for genetic markers. Chorion protein patterns were screened on thin-slab polyacrylamide isoelectric focusing gels. A wide range of polymorphism was observed between stocks. However, isoelectric focusing patterns obtained within a stock were nearly homogeneous, indicating that inbreeding has produced a high degree of homozygosis. Testcrosses were carried out to examine the linkage relationships between electrophoretic markers in four inbred stocks. One race (C108) was selected as a standard against which to compare the inheritance of the variants found in the other three stocks. Chorion markers behaved like codominant Mendelian traits in F, crosses. A total of 15 out of 16 C108 markers cosegregated in subsequent testcrosses, indicating that they are linked. These genes were mapped to the second chromosome, using markers Gr and Y.
D000818:Animals; D012831:Bombyx / Q000235:genetics*; D002823:Chorion / Q000378:metabolism*; D002875:Chromosomes; D004586:Electrophoresis; D005796:Genes; D008040:Genetic Linkage; D007525:Isoelectric Focusing; D011110:Polymorphism, Genetic; D011506:Proteins / Q000235:genetics*
D011506:Proteins