22 February 2018

Gutekunst and colleagues, 2018

Gutekunst J, Andriantsoa R, Falckenhayn C, Hanna K, Stein W, Rasamy J, Lyko F. 2018. Clonal genome evolution and rapid invasive spread of the marbled crayfish. Nature Ecology and Evolution 2(3): 567–573. https://doi.org/10.1038/s41559-018-0467-9


The marbled crayfish Procambarus virginalis is a unique freshwater crayfish characterized by very recent speciation and parthenogenetic reproduction. Marbled crayfish also represent an emerging invasive species and have formed wild populations in diverse freshwater habitats. However, our understanding of marbled crayfish biology, evolution and invasive spread has been hampered by the lack of freshwater crayfish genome sequences. We have now established a de novo draft assembly of the marbled crayfish genome. We determined the genome size at approximately 3.5 gigabase pairs and identified > 21,000 genes. Further analysis confirmed the close relationship to the genome of the slough crayfish, Procambarus fallax, and also established a triploid AA’B genotype with a high level of heterozygosity. Systematic fieldwork and genotyping demonstrated the rapid expansion of marbled crayfish on Madagascar and established the marbled crayfish as a potent invader of freshwater ecosystems. Furthermore, comparative whole-genome sequencing demonstrated the clonality of the population and their genetic identity with the oldest known stock from the German aquarium trade. Our study closes an important gap in the phylogenetic analysis of animal genomes and uncovers the unique evolutionary history of an emerging invasive species.

Keywords: comparative genomics • evolutionary genetics • invasive species

Vogt, 2018

Vogt G. 2018. Investigating the genetic and epigenetic basis of big biological questions with the parthenogenetic marbled crayfish: A review and perspectives. Journal of Biosciences 43(1): 189-223. https://doi.org/10.1007/s12038-018-9741-x


In the last 15 years, considerable attempts have been undertaken to develop the obligately parthenogenetic marbled crayfish Procambarus virginalis as a new model in biology. Its main advantage is the production of large numbers of offspring that are genetically identical to the mother, making this crustacean particularly suitable for research in epigenetics. Now, a draft genome, transcriptome and genome-wide methylome are available opening new windows for research. In this article, I summarize the biological advantages and genomic and epigenetic features of marbled crayfish and, based on first promising data, discuss what this new model could contribute to answering of “big” biological questions. Genome mining is expected to reveal new insights into the genetic specificities of decapod crustaceans, the genetic basis of arthropod reproduction, moulting and immunity, and more general topics such as the genetic underpinning of adaptation to fresh water, omnivory, biomineralization, sexual system change, behavioural variation, clonal genome evolution, and resistance to cancer. Epigenetic investigations with the marbled crayfish can help clarifying the role of epigenetic mechanisms in gene regulation, tissue specification, adult stem cell regulation, cell ageing, organ regeneration and disease susceptibility. Marbled crayfish is further suitable to elucidate the relationship between genetic and epigenetic variation, the transgenerational inheritance of epigenetic signatures and the contribution of epigenetic phenotype variation to the establishment of social hierarchies, environmental adaptation and speciation. These issues can be tackled by experiments with highly standardized laboratory lineages, comparison of differently adapted wild populations and the generation of genetically and epigenetically edited strains.

Keywords: cancer resistance • disease susceptibility • DNA methylation • environmental adaptation • epigenetics • genomics • immunity • marbled crayfish • regeneration • speciation

17 February 2018

Marenkov and colleagues, 2017

Marenkov O, Holoborodko K, Voronkova Y, Gorban V. 2017. Effect of zinc and cadmium ions on histostructure of antennal glands of marbled crayfish Procambarus fallax (Hagen, 1870) f. virginalis (Decapoda). Acta Biologica Universitatis Daugavpiliensis 17(2): 219–224. http://sciences.lv/wp-content/uploads/2018/01/Marenkov.pdf


Research results about the effects of cadmium and zinc ions on the histological structure of cells of antennal glands of marbled crayfish Procambarus fallax (Hagen, 1870) f. virginalis
(Decapoda) are presented in the article. It is determined that size of glandulocytes and their nuclei affected by to heavy metals naturally reduces however nuclear-cytoplasmic ratio is stably preserved, which is probably the excretory system adaptive response to the impact of heavy metals ions.

Keywords: cadmium • zinc • marbled crayfish • glandulocytes • Procambarus fallax (Hagen, 1870) f. virginalis

06 February 2018

Global Register of Introduced and Invasive Species

Pagad and colleagues (2018) have a new paper about the Global Register of Introduced and Invasive Species. Naturally, I went looking for Marmorkrebs.

The first interesting thing is that Marmorkrebs appeared in the database with four different species name variations:

  • Procambarus fallax (incomplete)
  • Procambarus fallax f virginalis (missing period)
  • Procambarus fallax f. virginalis (correct)
  • Procambarus fallaxformvirginalis (even if spaces were added, would be wrong: “form” should be “forma”)

You can’t search for common names, for the looks of things, just Latin ones. We will have to wait and see whether the proposal to change the name of Marmorkrebs to Procambarus virginalis will reduce the number of variations in lists like these, or just be one more variant to search for.

The second interesting thing is that are only four countries on the list: Germany, Sweden, Croatia, Ukraine. The map of Marmorkrebs introductions that I curate has six more: Madagascar, Japan, Italy, Hungary, the Czech Republic, Slovakia, and the Netherlands. It will be interesting to check in from time to time to see how long it takes for this to be updated.


Pagad S, Genovesi P, Carnevali L, Schigel D, McGeoch MA. Introducing the Global Register of Introduced and Invasive Species. Scientific Data

External links

Global Register of Introduced and Invasive Species 5: 170202. https://doi.org/10.1038/sdata.2017.202

05 February 2018

Marmorkrebs genome news round-up

The first crayfish genome is done, and it’s Marmorkrebs!

I normally don’t cover pre-prints in the blog, preferring to wait until the final, paginated version is out. But the pre-print for the Marmorkrebs genome by Gutekunst and colleagues is attracting international attention from journalists, and its Altmetric score is climbing fast. This post will collect news articles related to this paper.

I’ve been waiting the better part of a decade for this. After blogging about this in 2009, I’ve complained about the lack of a crayfish genome for years (2011, 2012, 2015, and 2016 at least). The portal for the genome is here.

This paper also provides the second major snapshot of the spread of Marmorkrebs in Madagascar. While previous papers showed it was in many places around the capital, this one shows just how far Marmorkrebs has spread.

5 February 2018

Invasion of the clones – Frank Lyko, Nature Ecology and Evolution “Behind the paper” blog post

A clonal crayfish from nature as a model for tumors – EurekAlert press release

An aquarium accident may have given this crayfish the DNA to take over the world – Elisabeth Pennisi, Science (duplicated, with different byline, here)

A pet crayfish can clone itself, and it’s spreading around the world - Sarah Zhang, The Atlantic (reprinted “‘We’re being invaded by an army of clones’; Plot twist: They’re crawfish” with “Advocate staff” byline in The Advocate)

This mutant crayfish clones itself, and it’s taking over Europe – Carl Zimmer, The New York Times (reprinted in the Toronto Star, Pittsbugh Post-Gazette, Deccan Herald)

Cloned crayfish conquers the world – Stephen Fleischfresser, Cosmos

Attack of the clones: Creature that started as pet now multiplying out of control
– Kristin Hugo, Newsweek

Marmorkrebs-Klone übernahmen Madagaskar in nur einem Jahrzehnt (Marble crayfish clones took over Madagascar in just a decade) – Jan Osterkamp, Spektrum der Wissenschaft

Marmorkrebse: Weltweite Ausbreitung durch Klone (Marble crayfish: Worldwide spread by clones) – Pharmazeitische Zeitung

Invasion der Krebsklone (Invasion of the crayfish clones)ORF.at

Crayfish evolved from pet to pest - Nature Asia blog

A species of crayfish has the ability to clone itself – Jonathan Kesh, Outer Places

Marmorkrebs: Eine Klon-Armee dient der KrebsforschungBR

6 February 2018

Mutant crayfish learned to clone itself in a German pet store and is now taking over Europe – Immanuel Jotham, International Business Times

Mutant crayfish invading the world originates from 1 single femaleRT

Significant Digits For Tuesday, Feb. 6, 2018 – Walt Hickey, Five Thirty Eight

Growing population of crayfish has one female ancestor Sarah Gibbens, National Geographic

Female mutant crayfish that can CLONE themselves are multiplying out of control and taking over parts of Europe and Africa – Cecile Borkhataria, The Daily Mail

Real life crayfish are born pregnant just like fictional Star Trek Tribbles – Brian Wang, Next Big Future

Geneticists unravel secrets of super-invasive crayfish – Ewan Callaway, Scientific American

The mutant, all-female crayfish that reproduce by cloning themselves – Natasha Frost, Atlas Obscura

Massive crayfish that didn’t exist 25 years ago are capable of cloning themselves — and it's terrifying scientists – Ashley Lutz, Business Insider (also Business Insider Nordic and Science Alert)

This little crayfish could take over the world – Noel Kirkpatrick, Earth Matters

Scientists say marbled crayfish have the DNA to take over the worldOutdoorHub

Mutant crayfish goes from zero to teeming in 25 years: video – Janet Pickel, PennLive

A mutant species of crayfish that reproduces asexually is taking over Europe – seriously! – Aaron Homer, The Inquisitr

Cloned pet crayfish self-spawning out of control – Clyde Hughes, Newsmax

These all-female, asexually reproducing mutant crayfish are the future liberals want – Julia Reinstein, BuzzFeed News (URL hints at original title: “Bring on the craytriarchy”)

Mutant, self-cloning crayfish are our new feminist #goals – Heather Schwedel, Slate

‘Cloverfield’ crayfish created a new species of self-replicating female mutants – Jamie Seidel, News.com.au (also at Fox News, New York Post, Springfield Daily Record, and NT News)

Mutant crayfish got rid of males, and its clones are taking over the world – John Timmer, Ars Technica (reprinted at SogoTech News)

‘They're coming!’: Mutant all-female crayfish are cloning themselves at an incredible rate - Wolfgang Stein interview, As It Happens

Marbled crayfish that can clone themselves originated from one mutant ancestor – Allan Adamson, Tech Times

A invasão dos clones: espécie mutante de lagostim se espalha pelo mundo – Sergio Matsuura, O Globo

Kreeft geeft wellicht meer zicht op kanker – Willen Schoonen, De Morgen

Georgia crawfish mutates into new species, takes over Europe – Christopher Buchanan, WXIA Atlanta

Mutant female crawfish invade Europe: report – Todd Price, NOLA.org

This self-cloning crawfish is invading Europe, report says – Jacqueline Quynh, Kevin Dupuy, WWL TV

7 February 2018

All-female crayfish species that didn’t exist 30 years ago reproduces by cloning itselfBT

Voracious mutant female crayfish clone themselves, taking over worldNewshub

Il gambero che si clona e va alla conquista del mondo (The shrimp that clones and goes to conquer the world) – Focus

自分自身のクローンを作り出して爆発的に増殖していくザリガニ (Crayfish that grow their own clones and grow explosively) – LiveDoor news

All-female mutant crayfish that clone themselves are taking over rivers and lakes around world - Josh Gabbatiss, The Independent

Mutant, all-female crayfish spreading rapidly through Europe can clone itself – Patrick Barkham, The Guardian (also at Gulf News Europe)

Shell shock: why crayfish replicants are taking overThe Guardian

All-female crayfish species that didn’t exist 30 years ago reproduces by cloning itselfAberdeen Evening Express

A mutant crayfish is cloning itself – Vadim Caraiman, Health Thoroughfare

Texas Standard: February 7, 2018 (mp3 file) - Zen Faulkes interview (starting at 25:44), Texas Standard, National Public Radio

Cloned Crayfish – Or Is It Crawfish – Could Be Coming To Texas Waters – Michael Marks, KUT (based on Texas Standard interview above)

Could the process that has apparently caused natural parthenogenesis in marbled crayfish be applied to cause parthenogenesis in humans? – Quora question

What do you think about the marble crayfish’s “cloning” ability? – Quora question

Marmorkrebs - Resistente Keime - Wasserstoffautos - Handyklau - WDR 5 Leonardo - Wissenschaft und mehr (mp3 file) – Science on Player FM (podcast)

Who needs a man? All-female mutant crayfish taking over the world, scientists say – Fira Pizani, Atlanta Journal-Constitution (also at Palm Beach Post and Austin American-Statesman)

New ‘mutant’ crayfish species is entirely female and don’t need no man – Mike Wehner, BGR

25 years ago, a mutant American crayfish turned to asexual reproduction, and all of Europe's lakes are filling up with its clonesBoing Boing

Who needs a man, anyway? These mutant crayfish sure don't – Kyle Fitzpatrick, Popsugar

The attack of the mutant crayfish – Bill Colley, KLIX

All-female crayfish in Europe can clone itself – Jose Vanhorne, Intelligencer

Marbled crayfish that can clone themselves originated from one mutant ancestorBrinkwire

Die „Tausend Töchter“ des Klon-Krebses und wie sie der Krebsforschung helfen (The "thousand daughters" of clone crayfish and how they help cancer research) – Sibylle Kohlstädt, Labor Praxis

8 February 2018

Crayfish clones – Kerri Smith and Adam Levy, Nature Podcast segment

If a crayfish didn't exist 25 years ago, how did it come into being? – Quora question

Marbled crayfish population explosion result of self cloning - Joanna Lentini, Dive Photo Guide

Crayfish shocked scientists by cloning itselfNetral English

A “parthenogenetic” crayfish reproduces without sex: is it a new species? – Jerry Coyne, Why Evolution is True blog

Marbled Crayfish Population Explosion Result of Self CloningViral News

Invasive new species of crayfish are cloning themselves – Chrissy Sexton, Earth.com

Cloning In nature: All marbled crayfish clones of one individual femaleCetus News

Scientists track spread of invasive crawfishUndercurrent News

Food for dirty thoughts: Sexual-fetish expert tantalizes with tales from her trade on BPR – Moses Jefferson, Brooklyn Paper Record podcast (seriously, there is discussion of marbled crayfish in there)

Crayfish that clones itself could be used as model for cancer research – Lauren Scrudato, Laboratory Equipment

Mutant clones of Georgia crawfish besiege planet – George Mathis, Atlanta Journal Constitution “News to Me” blog

Self-cloning mutant crayfish are taking over Europe, but really no big deal – Jeff Vrabel, Golf Digest

Mutant crayfish can clone itself and they are all females – Salve Juris, Kicker Daily News

9 February 2018

This crayfish has mutated into a super-gross tribble nightmare – Beth Elderkin, io9

The asexual clonal crayfish that could teach us about tumor development &ndash Alayna Hansen, New Atlas

Crayfish clone invasionGenome Web

ICYMI: Sex lives of crayfish, CO2 Is “the gas of life,” & more – Paul Rauber, Sierra Club

I’m just a misunderstood marbled crayfish (overlord) who is certainly not planning world domination – Josh Sippie, McSweeney’s

All-female crayfish in Europe can clone itselfDuta

10-12 February 2018

Female mutant crayfish clones have landed, but government recommends you not buy one – Catherine Tunney, CBC

Feminine mutant crayfish clones have landed, however authorities recommends you not purchase one – Staff, Luxora Leader

Weird species of crayfish has mutated to the point they can clone themselves – Stewart Perrie, LAD Bible

Thumbs up, thumbs downHouston Chronicle blog

is it a shrimp? is it a prawn? no - it's super crayfish! – Alison Campbell, Bio Blog

Incredible species of crayfish are able to clone themselvesDollar Viral

Q&A: Will mutant crayfish impact future of crawfish? – Leigh Frillici, KPRC

11 of our best weekend reads – Kaly Soto, The New York Times

Evolution caught in the act: a Darwin Day sampler pack – Stephanie Savage, Miracle Girl blog

Crayfish can clone themselves and might take over the world – Jessica Goddard, BrainJet

This new species can clone itself by the thousands — and could help scientists understand cancer – Travis Gettys, Raw Story

Attack of the (crustacean) clones – Abby Bigler, The Quad

Self-cloning marbled crayfish spreading across the worldThe Week

New crayfish that doesn't need males to mate becomes all-powerfulBBC

Mutant all-female crayfish prompt invasive species fearsDeutsche Welle

The crayfish ditches reproduction, turns to cloning (study) – Jose Buttner, Regal Tribune

Mutant female crayfish can breed alone and multiply at alarming rate – Sean Morrison, Evening Standard

Mutant crayfish alarms experts around the world – Dan Taylor, Morning Ticker (also at
Build a Better World News)

12 February 2018

Self-cloning marbled crayfish spreading across the world – Rebecca Gillie, MSN News

Attack of the clones: animal parthenogenesis – mountainwashere, Steemit

Crayfish Spiders Bees Grouse and Ungulates – Hurst and Carol, Creature Feature blog

14 February 2018

Klonende kreeft kan kankeronderzoekers inspireren (Cloning crayfish can inspire cancer researchers) – Gemma Venhuizen, NRC Handelsblad

These asexual animals don’t need love on Valentine’s Day (or any day) – Ryan F. Mandelbaum, Gizmodo

Self-reproducing crayfish species threatens ecosystems around the world – Jerry Xia, IR Insider

15 February 2018

Lang’s World: Ten Pearls of Whitaker’s wit and wisdom on sports and beyond 2.15.18 – Lang Whitaker, Grind City Media / Memphis Grizzlies

16 February 2018

Is the new species, Marmorkrebs, resulting from a crayfish genetic mutation an invasive new species or an evolutionary change? What are the benefits asexual cloning similar to tribbles on the legendary Star Trek episode?Quora question

19 February 2018

The crisis with crayfish – Lobsters that breed like Star Trek’s tribbles are conquering Europe
– Michael Rosch, Adventures in Poor Taste

22 February 2018

News of the Weird: Feb. 22, 2018 – Editors at Andrews McNeel Syndication, Shepard Express

News of the Weird: A Valentine's Divorce – Editors at Andrews McNeel Syndication, Creative Loafing

1 March 2018

God’s natural cloning – Anonymous, Does God Exist? Today blog

6 March 2018

Creationists and crayfish – Raymond Ramirez, The Observer (student newspaper)

Mutant strain of crayfish damages wetlands – Harold Allison, Washington Times Herald

9 March 2018

The wider debate about workplaces gives facilities managers a chance to crack the code
– Mark Eltringham, Insight

Tribbles and crayfish – William V. Raszka, AAP Journals blog

Related posts

Olivia’s fantasy genomes

External links

The genome portal for the marbled crayfish

16 January 2018

Kubiak and Pellett, 2018

Kubiak M, Pellett S. 2018. Invasive alien species legislation: a veterinary perspective. Companion Animal 23(1): 44-48. https://doi.org/10.12968/coan.2018.23.1.44


The European Union (EU) Invasive Alien Species (IAS) Regulation (1143/2014) restricts keeping of named species, in order to preserve native biodiversity. As some of these species are currently kept by private exotic animal keepers, zoological collections and animal encounter businesses, it is important for veterinary surgeons to be aware of the restrictions. As of August 2017, new species have been added to the legislation; this article reviews the previous situation and includes the updated information.

Keywords: invasive alien species • legislation • Tamias sibiricusProcyon lotorTrachemys scriptaNasua nasua

Maguire and colleagues, 2018

Maguire I, Klobučar G, Žganec K, Jelić M, Lucić A, Hudina S. 2018. Recent changes in distribution pattern of freshwater crayfish in Croatia − threats and perspectives. Knowledge and Management of Aquatic Ecosystems 419: 2. https://doi.org/10.1051/kmae/2017053


Analysis of Croatian freshwater crayfish populations, aiming to gather new distributional data and complement previous surveys (2005–2011), was performed during 2014–2016, within the frame of Natura 2000 Integration Project. The research included different waterbodies across the whole of Croatia, harbouring both indigenous and non-indigenous crayfish species (ICS and NICS, respectively). Field work was conducted in 117 grid squares with dimensions 10 × 10 km, and up to four waterbodies were surveyed per grid square, making a total of 450 studied sites. Out of those, crayfish were not recorded in 368 sites. In the sites with crayfish presence (i.e., 82), the most frequently observed ICS was Astacus astacus (registered in 33 sites) followed by Austropotamobius pallipes (16 sites), Austropotamobius torrentium (12 sites), and Astacus leptodactylus (5 sites). Concerning NICS, the majority of records were for Orconectes limosus (13 sites), followed by Pacifastacus leniusculus (2 sites), whereas Procambarus fallax f. virginalis was registered in only one locality. Comparisons of obtained data with those from previous surveys showed that NICS are progressively spreading and displacing ICS, as recorded for A. leptodactylus that was almost completely displaced by O. limosus in waterbodies of the east Croatia. Existing ICS populations are under growing anthropogenic preassure, frequently fragmented and isolated. Moreover, this survey showed that in the last decade 55% of A. astacus and 67% of A. pallipes populations disappeared mainly as a consequence of anthropogenic influence onto their habitats. Further monitoring and conservation actions for ICS should be urgently applied to mitigate negative impacts of both NICS and anthropogenic influence.

Keywords: noble crayfish • narrow-clawed crayfish • stone crayfish • white-clawed crayfish • non-indigenous crayfish species