Archive for paper

Genome sizes of termites

One of our papers on the genome sizes of termites and related insects (i.e. cockroaches) was recently accepted and the article is now available on line.

Koshikawa S, Miyazaki S, Cornette R, Matsumoto T, Miura T. 2008. Genome size of termites (Insecta, Dictyoptera, Isoptera) and wood roaches (Insecta, Dictyoptera, Cryptocercidae). Naturwissenschaften: in press. [doi: 10.1007/s00114-008-0395-7]

ABSTRACT – The evolution of genome size has been discussed in relation to the evolution of various biological traits. In the present study, the genome sizes of 22 dictyopteran species were estimated by Feulgen image analysis densitometry and 6-diamidino-2-phenylindole (DAPI)-based flow cytometry. The haploid genome sizes (C-values) of termites (Isoptera) ranged from 0.58 to 1.90 pg, and those of Cryptocercus wood roaches (Cryptocercidae) were 1.16 to 1.32 pg. Compared to known values of other cockroaches (Blattaria) and mantids (Mantodea), these values are low. A relatively small genome size appears to be a (syn)apomorphy of Isoptera + Cryptocercus, together with their sociality. In some phylogenetic groups, genome size evolution is thought to be influenced by selective pressure on a particular trait, such as cell size or rate of development. The present results raise the possibility that genome size is influenced by selective pressures on traits associated with the evolution of sociality.

Sphinx – an RNA gene that changes male fly behavior

Recently I’ve had many chances to hear about behavior-related genes in a fruitfly Drosophila melanogaster

I’ve just heard about a scientific news on a behavior gene, called “sphinx”.

Male-Male Courtship Pattern Shaped By Emergence Of A New Gene In Fruit Flies

This gene, that is expressed in male reproductive glands, was identified in 2002 as a non-protein-coding gene. The loss-of-function male flies for this gene are said to be attracted by other males, not by females.

In a brand-new paper published in May-27 issue of PNAS, the authors are analyzing the function of the gene, the news said.

I am very much interested in how this non-coding RNA changes the mating behavior. I will read the article tomorrow.