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.


Carl Zimmer

I recently found an exciting blog site “The Loom” written by Carl Zimmer, who is an outstanding science writer. His well-known works are “Parasite Rex”, “Evolution: The Triumph of an Idea”, “The Descent of Man”, etc. And he recently published “Microcosm: E. coli and the New Science of Life”.  I only have a Japanese edition of “Evolution”, which gives us very exciting and suggestive stories related to the evolution of life. I would like to read through the series of his works, too.

Below, I put the movie of his lecture entitled “The Evolution of Mind”.  We can learn lots about the human evolution from him.

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Recent jobs

It has been lots of months, probably longer than a year,  since I did my last experiments in the lab. These days, most of my time is spent for writing papers and/or grants, preparing presentations and/or lectures, and many other stuffs related to administration.

Among those things, I prefer writing and reading scientific papers, thinking about biology and science.  Frequently, I tend to lose many hours just for thinking about those things, especially about how to understand evolution.

In addition to the scientific studies in my lab, recently, I am engaged in some works for international collaborations. Those collaborative works are actually exciting but need some plenty of time.

Although the recent productivity of my lab is actually high, I think that I am fond of and good at experiments and observations, so that I wish I would have more time to get in touch with raw materials like insects.

Summer Meetings

This summer, I will attend the two international meetings, both of which will be held in the US. The one is Evolution 2008 in Minnesota, June 20-24, and the other is Pea Aphid Genome Annotation Workshop in Princeton, July 14-15.

After Evolution 2008, I will visit a lab in Wisconsin, where one of my lab member has just moved this spring. There, I will have to give a talk. So, I havee to prepare two talks and a poster, for those two visits to the US.

It’s about the time to start preparing those presentations…

aphid nymphs

Several days ago, a microscope company performed demonstration of a brand-new high quality degital microscope. At the time, one of our study material, aphids, were observed with it. I liked the “full focus” or “quick depth composition” function, that enabled us to take very nice insect photos with deep focus. That’s really fantastic!

By the way, these first-instar aphid nymphs look very cute with numerous fine hairs. Normally we can’t see those hairs with normal binocular microscopes. For our study on polyphenism, it is important to observe study materials very carefully, to find phenotypic differences even if they are trivial.

pixie dust

Do you know “pixie dust”?

It is a powder made from extracellular matrix of pig bladder. 

The powder has a mystery power to regenerate wounded organs, like to regrow a finger that was lost.

Probably the matrix can affect stem cells to launch proliferation, but the detailed mechanism is unknown.

If this remedy was generalized, wounded veterans could take their limbs back, for instance. Therefore, Pentagon has dedicated some big money to the research on this “pixie dust”, said the news below.

Salamander-inspired therapy may aid injured vets


Following is the BBC news on this topic.

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.

Parasitoid wasp

Last week, one of my colleague sent me this photo.

His son collected a lepidopteran worm to observe. Some days after that, the worm died with lots of weird stuffs.

I’m sure this is because of parasitoid wasp, which probably belongs to the family Braconidae. These parasitic wasps are really fascinating! The host insect species are diverse and the parasites adapt the life history and physiology of host species. 

I am not familiar with the parasitic wasps but the some wasps show phenotypic plasticity depending on host insect species. This sounds very interesting to me, so I will talk about this some time.


From the midnight, probably, it has been raining heavily. This is because a typhoon #200804, which is the first one for me this year, is now approaching Japan. So, I cannot use my bicycle to commute today.

This year, I am very busy because of lots of obligatory works and private things in addition to research activities. Furthermore, most of my research works are writing papers and grant proposals. I have been away from doing experiments by myself… that is actually frustrating to me…

Overseas trips this summer were over.

All of the overseas trips this summer was over.

I attended three meethings, which I’d been interested in for some time.

Evolution meeting (Christchurch, NZ; June 16-20), Daphnia Genome Consortium meeting (Bloomington, USA; July 7-9), and JH-IX (York, UK; August 5-10).

After those meeting, I’ve got tired a bit though, I’ve also got many new things to me.

I’m having lots of things that I want to do, but probably those are too many, so I have to think deeper and select some of them that is really required to be done.

Although meetings outside Japan were over, I still have lots of plans of domestic travels this year…

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