A Subtle Defect Underlies Altered Lamellar Orientation in the Gr16 Chorion Mutant of Bombyx mori

A genetic linkage map for the domesticated silkworm,Bombyx mori, based on restriction fragment length polymorphisms

“…Currently its genetic linkage map contains more than 200 markers on 28 linkage groups and covers nearly 1000 centimorgans (cM) (Doira, 1992). Most of these markers are morphological or physiological mutations affecting such fundamental processes as egg formation (e.g., see Kawaguchi & Doira, 1973;Kawaguchi et al 1983Kawaguchi et al , 1987Kawaguchi et al , 1988Kawaguchi et al , 1990Kawaguchi et al , 1993Fujikawa et al 1993) and choriogenesis (Nadel et al 1980 a, b;Gautreau et al 1993), embryonic patterning and segment identity (e.g., see Tazima, 1964;Ueno et al 1992Ueno et al , 1995, larval epidermal pigmentation (e.g., see Tamura, 1977Tamura, ,1983Tamura & Akai, 1990;Sakurai & Tsujita, 1976 a, b;Sawada et al 1990;Shimizu et al 1993), hormone action (Shimizu et al 1980;Nagata et al 1992), and diapause (Yamamoto et al 1978;Sonobe et al 1986) (see also Doira, 1978;Goldsmith, 1995). About 20 loci encode identified gene products such as isozymes, hemolymph, silk, and chorion proteins which were mapped using electrophoretic variants, or more recently, cloned neuropeptides localized via the polymerase chain reaction (Shimada et al 1994;Pinyarat et al 1995).…”

Identification and functional analysis of a novel chorion protein essential for egg maturation in the brown planthopper

“…Spatially restricted components of silkmoth eggshell were described, and 23 proteins were found entirely or predominantly in the aeropyle crown or stripe regions (Regier et al, 1980). Analyses of the silkmoth grey chorion mutations suggested the involvement of multiple minor chorion proteins in lamellar chorion organization (Gautreau et al, 1993). In other insects, Brownie, an abundantly expressed structural component of the sponge-like body of the Blattella germanica eggshell was identified to build up the aeropyle and micropyle structures (Irles et al, 2009a), and Citrus was considered to be a component of endochorion (Irles & Piulachs, 2011) in B. germanica.…”

Characterization of Early Follicular cDNA Library Suggests Evidence for Genetic Polymorphisms in the Inbred Strain C108 of Bombyx mori.

“…During the rearing, the silkworms were fed fresh mulberry leaves [obtained from the University of Rhode Island's East Farm or campus greenhouse]. DNA for the genetic studies was extracted from the posterior silkglands of 3-4 day old fifth instar larvae as previously described (Gautreau et al, 1993;Shi et al, 1995). Briefly, pairs of posterior silkglands were dissected and ground in 1 ml of warmed extraction buffer (0.5% sarkosyl, 50 mM EDTA, pH 8.0, and 0.5 mg/ml proteinase K) and incubated for 2-3 hours at 50°C.…”