Patterns of conservation and change in honey bee developmental genes

Abstract

The current insect genome sequencing projects provide an opportunity to extend studies of the evolution of developmental genes and pathways in insects. In this paper we examine the conservation and divergence of genes and developmental processes between Drosophila and the honey bee; two holometabolous insects whose lineages separated ∼300 million years ago, by comparing the presence or absence of 308 Drosophila developmental genes in the honey bee. Through examination of the presence or absence of genes involved in conserved pathways (cell signaling, axis formation, segmentation and homeobox transcription factors), we find that the vast majority of genes are conserved. Some genes involved in these processes are, however, missing in the honey bee. We have also examined the orthology of Drosophila genes involved in processes that differ between the honey bee and Drosophila. Many of these genes are preserved in the honey bee despite the process in which they act in Drosophila being different or absent in the honey bee. Many of the missing genes in both situations appear to have arisen recently in the Drosophila lineage, have single known functions in Drosophila, and act early in developmental pathways, while those that are preserved have pleiotropic functions. An evolutionary interpretation of these data is that either genes with multiple functions in a common ancestor are more likely to be preserved in both insect lineages, or genes that are preserved throughout evolution are more likely to co-opt additional functions.

Sexual Back Talk With Evolutionary Implications: Stimulation of the Drosophila Sex-Determination Gene Sex-lethal by Its Target transformer

“…Tephritidae, the ''true'' fruit flies, are evolutionary cousins of the Drosophilidae. Sxl orthologs have also been identified in the Tephritidae (Saccone et al 1998) and in insects as distant as honeybees (Dearden et al 2006) and moths (Niimi et al 2006); nevertheless, only in the Drosophilidae does Sxl appear to be sex-specifically regulated (Bopp et al 1996;Dorsett et al 2003). The view that in the Drosophilidae, Sxl took over tra's ancestral developmental role is supported by the recent discovery and experimental manipulation of feminizer ( fem), the honeybee tra ortholog (Hasselmann et al 2008).…”

Community annotation: Procedures, protocols, and supporting tools: Table 1.

“…Many of the findings were supported by laboratory experiments and developed into full research publications (Cho et al 2006;Collins et al 2006;Dearden et al 2006;Evans et al 2006;Forêt and The number of genes and gene models is summarized in Table 1. The number of gene models in the OGS increased from 10,157 to 10,314, despite 302 OGS models being dropped due to splits and merges.…”

Surprising flexibility in a conserved Hox transcription factor over 550 million years of evolution

“…In addition to these protein changes, ftz expression changed during arthropod evolution from a Hox-like domain in an arthropod ancestor (25,(36)(37)(38) to seven pair-rule stripes, seen in modern day drosophilids (39,40). Striped expression was also observed in the basal insect Thermobia (41) and two other holometabolous insects, the beetle Tribolium casteneum and the honey bee Apis mellifera (42,43), but stripes were absent in a grasshopper Schistocerca gregaria (44). This finding suggests that striped expression was either gained twice in arthropods, in a basal insect lineage and during early radiations of holometabolous insects, or was gained once in basal insects and lost in orthopteran lineages.…”