Carlos Chavez Ramirez
carloschalicothere.bsky.social
Carlos Chavez Ramirez
@carloschalicothere.bsky.social
Molecular Genetics, Neuroscience, Science Communication
Reposted by Carlos Chavez Ramirez
Fragments of proto-Earth found in Hawai'i, Greenland and Canada are older than the moon-forming impact (4.5 billion years ago) and have remained unaltered despite geological processes. www.nature.com/articles/s41... 🧪
Potassium-40 isotopic evidence for an extant pre-giant-impact component of Earth’s mantle - Nature Geoscience
Some mafic rocks have a ⁴⁰K/³⁹K ratio lower than all other terrestrial samples, according to isotopic composition analyses, suggesting parts of Earth’s mantle have retained their composition prior to ...
www.nature.com
October 22, 2025 at 4:23 PM
Reposted by Carlos Chavez Ramirez
🧪 How do cells clean up misfolded proteins when they divide?

This study finds that the cleanup crew includes the ER chaperone BiP and the proteasome, and kicks in right as cells finish dividing. Surprisingly, one major cell cycle regulator isn’t involved.
buff.ly/SC2lJH6
July 10, 2025 at 10:28 PM
Reposted by Carlos Chavez Ramirez
Computer algorithms have designed highly efficient synthetic enzymes from scratch.

The resulting enzymes catalyze a chemical reaction that no known natural protein can execute, achieving a reaction rate and efficiency similar to naturally occurring enzymes.

🧪🦠

www.nature.com/articles/d41...
‘Remarkable’ new enzymes built by algorithm with physics know-how
Computer approach creates synthetic enzymes 100 times more efficient than those designed by AI.
www.nature.com
June 19, 2025 at 1:07 AM
Reposted by Carlos Chavez Ramirez
Just published, expansion in situ genome sequencing, where you can sequence DNA while still inside the cell, mapping its organization relative to proteins and other markers, with the help of expansion microscopy! Led by @jbuenrostro.bksy.social. www.science.org/doi/10.1126/...
May 30, 2025 at 11:37 AM
Reposted by Carlos Chavez Ramirez
Policarpo et al. use phylogenetic and synteny data to identify 19 teleost-to-teleost horizontal gene transfers, involving genes linked to immunity or pore formation; this suggests eukaryote-to-eukaryote HGT has shaped teleost evolution.

🔗 doi.org/10.1093/molbev/msaf107

#evolbio #molbio #fish
Multiple Horizontal Transfers of Immune Genes Between Distantly Related Teleost Fishes
Abstract. Horizontal gene transfer (HGT) is less frequent in eukaryotes than in prokaryotes, yet can have strong functional implications and was proposed a
doi.org
May 28, 2025 at 9:14 AM
Reposted by Carlos Chavez Ramirez
Discover how bilaterians' gene regulation relies on chromatin loops and compartments. Did these 3D structures exist in ancestors? Curious minds engage! PMID:40335694, Nature 2025, @Nature https://doi.org/10.1038/s41586-025-08960-w #Medsky #Pharmsky #RNA #ASHG #ESHG 🧪
Chromatin loops are an ancestral hallmark of the animal regulatory genome | Nature
In bilaterian animals, gene regulation is shaped by a combination of linear and spatial regulatory information. Regulatory elements along the genome are integrated into gene regulatory landscapes through chromatin compartmentalization1,2, insulation of neighbouring genomic regions3,4 and chromatin looping that brings together distal cis-regulatory sequences5. However, the evolution of these regulatory features is unknown because the three-dimensional genome architecture of most animal lineages remains unexplored6,7. To trace the evolutionary origins of animal genome regulation, here we characterized the physical organization of the genome in non-bilaterian animals (sponges, ctenophores, placozoans and cnidarians)8,9 and their closest unicellular relatives (ichthyosporeans, filastereans and choanoflagellates)10 by combining high-resolution chromosome conformation capture11,12 with epigenomic marks and gene expression data. Our comparative analysis showed that chromatin looping is a cons
doi.org
May 12, 2025 at 6:10 AM
The Maned Wolf (Chrysocyon brachyurus) may look like a fox, but it’s neither a fox nor a wolf! A phylogenetic study using 15K bases of DNA shows it belongs to a distinct group of canids endemic to South America. #2025MMM #RIP www.nature.com/articles/nature04338
March 21, 2025 at 1:54 AM
Recent genetic work from Dutra et al. using nuclear and mitochondrial markers has shown that the chacoan peccary should be placed in the distinct genus Parachoerus in 2016. Their former genus 'Catagonus' is just a pig-ment of their imagination! #2025MMM link.springer.com/article/10.1...
March 21, 2025 at 1:47 AM
The Maned Wolf (C. brachyurus) has the longest legs of any canid! But what genes drive this extreme phenotype? A genomic study of it & its short-limbed cousin, the bush dog, found that B4GALT7 may play a key role in their striking limb length differences. #2025MMM www.pnas.org/doi/10.1073/...
March 21, 2025 at 1:46 AM
And if you thought that Quokkas only had trypanosome parasites, think again -- a novel gammaherpesvirus (MaHV-6) was detected by PCR in the blood of 13 of 121 individuals (11%) sampled in Western Australia. Check out all that viral diversity! #2025MMM #RIP dx.doi.org/10.1638/2020...
March 21, 2025 at 1:40 AM
Quokkas (Setonix brachyurus) are cute and all (smiley, etc) -- but did you know they have some parasitic friends? Trypanosomes are the unicellular flagellate protozoa that live in their bloodstream and steal nutrients from Quokka. Who's smiling now!? #2025MMM www.sciencedirect.com/science/arti...
March 21, 2025 at 1:29 AM
If it ain't broke, don't fix it! Studies using chromosome painting techniques have shown that all members of the family Felidae (including the puma) have 19 pairs of chromosomes (Wie et al. 2011), despite evolving at least 35 million years ago. #2025MMM www.nature.com/articles/hdy...
March 21, 2025 at 1:28 AM
Climate change threatens coastal species. Genomic analysis of two horseshoe crabs reveals that the less mobile Carcinoscorpius rotundicauda is losing genetic diversity faster than Tachypleus gigas, making it more vulnerable. Conservation efforts are needed. #2025MMM #RIP doi.org/10.1111/eva....
March 21, 2025 at 1:23 AM
Gars have a GC-compartmentalized genome, resembling mammals rather than other fish. This challenges the idea that GC heterogeneity arose with amniotes. Their metabolism may have driven DNA thermostability and genome evolution, supporting the metabolic rate hypothesis #2025MMM doi.org/10.1002/jez....
March 21, 2025 at 1:17 AM
The genome of Limulus polyphemus reveals 18 opsins, shedding light on chelicerate vision & opsin evolution. Phylogenetic analyses highlight key genomic events shaping its visual system, enhancing understanding of horseshoe crab photosensitivity & arthropod evolution #2025MMM doi.org/10.1093/gbe/...
March 21, 2025 at 1:15 AM
Since you won't be seeing any more of our friend the Spotted-necked Otter, here is a last look at more of his furry family -- the Otters of the World! Poster available for the low price of $8.99, can't say that's a bad deal (credit: Roger Hall)
#2025MMM #RIP inkart.net/product/otte...
March 21, 2025 at 1:10 AM
"The Spotted-necked Otter (Hydrictis maculicollis) used to be called ""Lutra maculicollis"" in case you got confused -- they are handsome devils and have 2n=40 chromosomes, making them only otter species with >38 chromosomes!
#2025MMM doi.org/10.1644/0.71... www.mammaldiversity.org/taxon/100584...
March 21, 2025 at 12:58 AM
Addax is at risk of extinction, w/ <300 individuals in the wild. Armstrong et al. (2010) studied a captive Addax population at the Parque Lecocq Zoo & found low genetic diversity & high inbreeding—a risk for conservation! #2025MMM doi.org/10.1002/zoo.20341
March 21, 2025 at 12:57 AM
Coelacanths have a unique adaptive immune system, w distinctive IgW loci, no IgM, & tetrapod-like immune genes. Their T-cell receptor organization mirrors tetrapods, raising questions about immune evolution and expanding our understanding of vertebrate immunity. #RIP #2025MMM doi.org/10.1002/jez....
March 21, 2025 at 12:50 AM
Ringed seals populations disperse all across the Arctic and may migrate long distances during the summer months. Martinez-Bakker et al 2014 found that the Lake Saimaa seals do not exchange many seals with other arctic populations and are genetically differentiated doi.org/10.1371/jour... #2025MMM
March 21, 2025 at 12:42 AM
The "living fossil" coelacanth has a 2.74 Gbp genome w 60% repetitive elements and low gen. diversity. It shares tetrapod-like olfactory genes and limb enhancers, hinting at early adaptations in Sarcopterygii and giving insights into fish-tetrapod transition. #2025MMM www.genome.org/cgi/doi/10.1...
March 21, 2025 at 12:40 AM
The most complex and rearranged vertebrate mitochondrial genome is found in the tuatara! Macey et al 2021 find all 37 common vertebrate genes with an extra three control region blocks, and duplicate tRNAs. The tuatara mt-genome shows drastic gene rearrangements #RIP #2025MMM doi.org/10.1038/s420...
March 21, 2025 at 12:35 AM
Roots and Relicts can help us understand the evolution of the skin. In vertebrates, this is controlled by the epidermal differentiation complex (EDC). Holthaus, et al 2020 identified EDC genes the tuatara and found them to be close to the snakes and lizards doi.org/10.1038/s415... #2025MMM
March 21, 2025 at 12:30 AM
🦈 Unlike most live-bearing animals, frilled sharks still keep egg yolk genes (VTG). A 2023 study found their genome actively retains these genes, helping sustain embryos for 3.5 years before birth (!!!). Evolution repurposes, rather than erases! #2025MMM doi.org/10.1093/gbe/...
March 21, 2025 at 12:27 AM
Forest tortoises determine whether they are born male of female based on the temperature of egg instead of relying on a genetic mechanism. Emer 2007 hatched male tortoises at low temperatures (24.99°C, 27.18°C) and female tortoises at high temperatures (30.79°C) doi.org/10.57709/105... #2025MMM #RIP
March 21, 2025 at 12:24 AM