Category Archives: News

A new transcriptome paper is published

A paper on transcriptome phylogeography of periodical cicada is now out.

Fujisawa, T., Koyama, T., Kakishima, S., Cooley, J. R., Simon, C., Yoshimura, J., & Sota, T. (2018). Triplicate parallel life cycle divergence despite gene flow in periodical cicadas. Communications Biology, 1(1), 26.

It is a detailed phylogeographic study of three species groups of Magicicada periodical cicadas. We found gene flows between geographically adjacent, closely related 13 year and 17 year species. We also searched for genes responsible for the life cycle control, but did not find any divergent loci shared by three species groups.


tr2-delimitation in python3

I just announce that the tr2-delimitation in Python3 is now available from the following repository.

It should return results exactly the same as the Python2 version (I verified it with the data set of the Fujisawa et al. (2016) paper).

I will maintain the old Python2 version, but the new functions will be added to this Python3 version.

New multilocus delimitation code

I just announce that the codes for the new multilocus delimitation method are available at my Bitbucket repository.

The new program is called “tr2”, which stands for “trinomial distribution of triplets” model. It delimits species from multilocus gene trees by measuring congruence of gene trees between species and incongruence within species. It calculates the posterior probabilities of two types of trinomial distribution models and test within/between-species boundaries. A closely related methods are MP-EST, the triplet-based phylogeny reconstruction method by Liu et al, and the Bayesian species delimitation method BP&P by Yang&Rannala.

The tr2 implements a rapid algorithm to find the best delimitation under a given guide tree and an optimality score (AIC or posterior probability), which can run with more than 100 tip guide trees.

If you are interested in it, please visit the repository below and try it.

I assume that users have knowledge of Python and related programming tools like Mercurial. The program is not well-decumented now. I will write down detailed instructions in following blog posts.

New papers on species delimitation

Some new papers on DNA based species delimitation have been published.

A paper about a mutilocus species delimitation method has just been published.

Fujisawa, T., Aswad, A. and Barraclough, T.G. (2016) A rapid and scalable method for multilocus species delimitation using Bayesian model  comparison and rooted triplets. Syst.Biol. doi: 10.1093/sysbio/syw028

It describes a new multilocus species delimitation method which is applicable to large data.

Another paper I coauthored is about the GMYC and taxon sampling.

Ahrens, D. Fujisawa, T., Krammer, HJ., Eberle, J., Fabrizi, S. and Vogler, A.P. (2016) Rarity and Incomplete Sampling in DNA-based Species Delimitation. Syst. Biol. doi:10.1093/sysbio/syw002

It is about empirical and simulation studies about the effects of different taxon sampling schemes on the single locus delimitation method.


A new paper

A new paper about molecular evolution of water beetles is now published.

Fujisawa, T., Vogler, A.P., Barraclough T.G. (2015) Ecology has contrasting effects on genetic variation within species versus rates of molecular evolution across species in water beetles. Proc. R. Soc. B. 282:20142476

It is about ecological correlates on species’ genetic variation and rate of molecular evolution. Also, it is an application of the GMYC delimitation to comparative analysis based on sequence databases.