Category Archives: animals

Meet Klara, the trasparent CRISPR fish

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The turquoise killifish is a small freshwater African fish and a model organism for studying aging. Now researchers will be able to observe the changes in individuals of this species (Nothobranchius furzeri) much more easily, as a German team has used CRISPR to inactivate three genes in one go, causing their vibrant pigmentation to disappear.

The transparent line, dubbed Klara, was presented on eLife, which also released this video on twitter. The idea is not new, in fact crystal-clear mutants of zebrafish and medaka already swim around in laboratories. But Klara is a valuable new arrival, especially for aging scientists. In fact, despite living only a few months to about a year, these fish show typical signs of mammalian aging including telomere shortening.

Brenner, CRISPR and the zebrafish

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“Progress in science is driven by new technologies, new discoveries, new ideas – in that order” (S. Brenner). This quote by one of the greatest biologists of the 20th century came to my mind while reading a curious paper recently published in Nature. To sum up, a group from Taiwan has discovered that some cells can divide despite an absence of DNA replication.

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Are you ready for CRISPR cats?

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The paper “Evolutionary Biology and Gene Editing of Cat Allergen Fel d 1” is a proof of principle but this is only the first step. About 15% of humans have allergic reactions to cats and the major allergen may be nonessential for those animals, given the apparent lack of evolutionary conservation. According to the bioinformatics analysis just published by Nicole Brackett et al. from the US company InBio “Fel d 1 is both a rational and viable candidate for gene deletion, which may profoundly benefit cat allergy sufferers by removing the major allergen at the source”.

Xenotransplantation: time to go deeper

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Photo credit: Joe Carrotta

And so it happened. “In a first, surgeons attached a pig kidney to a human, and it worked,” as the New York Times puts it. Data are scarce, however, and all the info we have is from the general media. The kidney came from a GalSafe pig, which is the only one FDA approved so far. But scientists from several companies have already developed pigs much more engineered than that (with three or four porcine genes knocked-out instead of one, and human gene additions). To get an updated picture, we highly recommend this article published in Nature Biotechnology last April.

GM mosquitoes play rock paper scissors

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Anti-CRISPR proteins are the rock needed to stop CRISPR-based mosquito-eradicating gene drives, if necessary, and make them safer. In a news feature published last year in Nature, the molecular parasitologist Andrea Crisanti disclosed unpublished data about halting an anti-malaria gene-drive system by adding anti-drive mosquitoes to the mix. “They can completely, 100% block the drive. We can stop the [Anopheles gambiae] population from crashing,” he said. According to the scientist from the Imperial College London, it’s kind of like buying an insurance. Looking ahead to field-testing his sterilization strategy, Crisanti imagined having cages of anti-drive mosquitoes at the ready, just in case things go awry. Well, that work is now published, and anti-drive mosquitoes are a reality. To learn more, see the paper published on June 25 in Nature Communications by Chrysanthi Taxiarchi et al.

Where is the revived mammoth?

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I watched Genesis 2.0, which is debuting in Italy almost two years after its release at the Sundance Film Festival. In the meanwhile, Semyon Grigoriyev has died. The Russian paleontologist leading the effort to clone a mammoth was one of the movie’s main characters. He always had little chance of success, and the plan’s odds are now worse than ever.

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Edited shells turn left

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snail crispr cover

Most snails live in right-coiled shells, and the general rarity of sinistral gastropods has long attracted comment and wonder, according to the late Stephen Jay Gould. “Aristotle declared them impossible, but d’ Argentville called them uniques, while Geoffroy dubbed them nonpareilles. Since no one has ever developed an even vaguely plausible argument for dextral advantage, the overwhelming predominance of right-handed coiling among gastropods has been a persistent puzzle.” Continue reading →