Characterisation of white and yellow eye colour mutant strains of house cricket, Acheta domesticus

Abstract

Two eye-colour mutant strains, white (W) and yellow (Y) of house cricket Acheta domesticus were established in our laboratory. We phenotyped and genotyped the mutants, performed genetic crossings and studied the eye structure and pigment composition using light and electron microscopy and biochemical analysis. We show that W and Y phenotypes are controlled by a single autosomal recessive allele, as both traits are metabolically independent. The analysis of the mutants`eye structure showed a reduced number of dark pigment granules while simultaneously, and an increased amount of light vacuoles in white eye mutants was observed. Significant differences in eye pigment composition between strains were also found. The Y mutant had a lower number of ommochromes, while the W mutant had a lower number of ommochromes and pteridines. This indicates that mutated genes are involved in two different, independent metabolic pathways regulating tryptophan metabolism enzymes, pigment transporter granules or pigment granule formation.

Efficient CRISPR/Cas9-mediated genome modification of the glassy-winged sharpshooter Homalodisca vitripennis (Germar)

“…We were able to unequivocally demonstrate that w and cn are located on autosomes; furthermore, genotyping of both w and cn mutant individuals from G1, G2 and G3 indicated that both males and females carried two alleles for each of these genes. This contrasts to the X-linked inheritance of w in D. melanogaster 49 , but is consistent with the autosomal location of w in the hemimetabolous house cricket, Acheta domesticus 50 . Given the conservation of X-linked genes in three hemipteran insects ( O. fasciatus , the brown marmorated stink bug ( Halyomorpha halys) and GWSS) with different sex determination systems (XX/XY, likely male heterogametic , and XX/XO, respectively ), it will be interesting to determine if the autosomal location of w will be maintained across the Hemiptera 48 .…”

Chemical structure and antioxidant activity of cephalopod skin ommochrome pigment extracts

“…The spectra matched the ommatin group of ommochromes (Sawada et al, 2000). The wide bands (360-650 nm) are attributed to a combination of different ommochrome compounds (Liu et al, 2012;Francikowski et al, 2019). The main absorbance peaks detected in ommochromes can shift; however, the most common shifts reported for xanthommatin and dihydroxanthommatin are observed in the UV, near UV, and 430-520 nm ranges (Riou & Christidès, 2010;Figon & Casas, recorded at 734 nm using a UV spectrophotometer (Multiskan GO, Thermo Scientific).…”

Testing for fitness epistasis in a transplant experiment identifies a candidate adaptive locus inTimemastick insects

“…However, the most intriguing candidate gene ( predicted gene g6064) is located approximately 118 kilobase pairs away from outlier 2 and is homologous to the Punch (Pu) gene in D. melanogaster (table 1). This gene codes for a GTP cyclohydrase I enzyme, which is involved in the first step of the production of pteridine pigments in D. melanogaster and other insects, and is associated with eye and body coloration in multiple insect species [37][38][39][40]59]. This led us to hypothesize that this SNP could also be associated with T. chumash eye coloration, a trait that we observed to be quite variable but which is previously unstudied in this species (electronic supplementary material, figure S2).…”

“…Chitinases are associated with cold or heat stress tolerance in several insect species [35,36] suggesting that this locus could be associated with heat tolerance in Timema. However, the most intriguing candidate, Punch, controls the first step of pteridine pigments production and is associated with eye and body coloration in many insect species [37][38][39][40]. This led us to hypothesize that this locus could be primarily associated with eye colour variation in T. chumash.…”