07 June 2011

Vogt, 2011

Vogt G. 2011. Marmorkrebs: natural crayfish clone as emerging model for various biological disciplines. Journal of Biosciences 36(2): 377-382.
http://dx.doi.org/10.1007/s12038-011-9070-9

Without abstract. These are the section headings of the paper:

  1. What is the Marmorkrebs?
  2. How do marbled crayfish reproduce and develop?
  3. Is it true that the first juvenile stages are secured by a safety line?
  4. Why are marbled crayfish so attractive to researchers?
  5. How can marbled crayfish produce different phenotypes from a single genotype?
  6. Is negligible senescence in the marbled crayfish related to lifelong stem cell activity?
  7. Is it true that marbled crayfish are highly resistant to cancer?
  8. Are marbled crayfish good guys only?
  9. How can I be kept informed about ongoing research with the marbled crayfish?

Keywords: cancer • development • genotype-to-phenotype mapping • marbled crayfish • model organism • stem cells

The Crustacean Society 2011: Day 1

Do you think this audience is ready to hear a talk about clones tomorrow?


We were all instructed to wear our conference shirts for the group photo.

Tonight was just an opening reception, which included a Hawaiian blessing and some demonstrations of traditional and modern hula. It was quite lovely and very enjoyable.


06 June 2011

The Crustacean Society 2011: Preamble


Aloha!

This week I'm blogging from The Crustacean Society meeting in Honolulu, Hawaii! So expect a lots of crunchy biological goodness both here and at NeuroDojo. I'll also be tweeting a bit, I hope, using #tcs11 as the hashtag.

But now, time to find some breakfast.

31 May 2011

Another (occasionally) parthenogenetic crayfish

ResearchBlogging.orgI not sure how to describe the sound I made when I saw the title of this paper, but it was not a quiet sound. I immediately thought, “This is huge.”

A new paper in PLoS ONE reports that spinycheek crayfish (Orconectes limosus) can reproduce by parthenogenesis. Unlike a previous report of red swamp crayfish (Procambarus clarkii) reproducing by parthenogenesis, which based its claim on similar DNA from adults and no actual observed instances of reproduction, this paper claims to have isolated females that have reproduced.

The animals were taken from the wild and reared as adults, which immediately makes one think “sperm storage.” The authors argue that the genetic similarity of the offspring rules this out. I think an obvious next step is to see if juveniles born in the lab without sex can be reared through an entire generation, and in turn produce more offspring without meeting males.

This is a bombshell. It suggests that asexual reproduction in crayfish is more common than thought, particularly when the P. clarkii paper is also hinting that they can do the same. From an evolutionary point of view, this would mean that the evolution of the completely asexual lineage of Marmorkrebs may not have been as insurmountable as it first appeared.

Reference

Buřič M, Hulák M, Kouba A, Petrusek A, Kozák P. 2011. A successful crayfish invader is capable of facultative parthenogenesis: a novel reproductive mode in decapod crustaceans. PLoS ONE 6(5): e20281. http://dx.doi.org/10.1371%2Fjournal.pone.0020281

Picture from here.

LOLcray


Based on picture here.

24 May 2011

Filipová and colleagues, 2011

Filipová L, Grandjean F, Chucholl C, Soes DM, Petrusek A. 2011. Identification of exotic North American crayfish in Europe by DNA barcoding. Knowledge and Management of Aquatic Ecosystems 401: 11. http://dx.doi.org/10.1051/kmae/2011025

Abstract

Several alien crayfish of North American origin have become established in Europe in recent decades, but their identification is often confusing. Our aim was to verify the taxonomic status of their European populations by DNA barcoding. We sequenced the cytochrome c oxidase subunit I (COI) gene fragment of individuals representing all American crayfish known from European waters, and compared the results with reference sequences from North America. Our results confirm the morphological identification of Orconectes juvenilis from a population in eastern France, and of the marbled crayfish (Marmorkrebs), i.e., a parthenogenetic form of Procambarus fallax, from south-western Germany. Sequences of most individuals of presumed Procambarus acutus from the Netherlands were similar to American P. cf. acutus, but one was divergent, closer to a sequence of a reference individual of P. cf. zonangulus. However, divergences among three American P. cf. zonangulus samples were also high, comparable to interspecific variation within cambarid species complexes. The divergence between O. immunis from Europe and America also reached values corresponding to those observed among distinct Orconectes species. Genetic variation in the American range of these crayfish should therefore be further studied. Our study shows that DNA barcoding is useful for the rapid and accurate identification of exotic crayfish in Europe, and also provides insights into overall variation within these taxa.

Keywords: COI • barcoding • invasive crayfish • Europe • North America • Orconectes • Procambarus

17 May 2011

Dot com

I’m embarrassed to admit that once in a while, I wasn’t able to get to my own website on the first try.

If you live in North America and type in a domain name, what do you normally do after you get to the dot? You start typing “com”. It’s easy to forget about other domain names like “net” or “org” entirely.

But I won’t have that problem any more. And neither will anyone else. The Marmorkrebs website can now be reached by through Marmorkrebs.com.

Photo by RambergMediaImages on Flickr; used under a Creative Commons license.