A team of researchers from Thomas Jefferson University, Philadelphia, the University of Southern California, the Beckman Research Institute of the City...
An international team of zoologists from Australia and China has discovered two new cryptic species in the genus Eupetaurus — which previously included...
The newly-discovered fossilized footprints were made by at least two mammalian species around 58 million years ago in a brackish water lagoon in what is...
Fossiomanus sinensis and Jueconodon cheni, two distantly related species of mammaliamorphs that lived some 120 million years ago (Early Cretaceous epoch),...
Paleontologists from the United States and China have examined the middle ear bones (ossicles) of Vilevolodon diplomylos, a gliding haramiyidan that lived...
Monotremes (egg-laying mammals) are the only extant mammalian outgroup to therians (marsupial and eutherian animals) and provide key insights into mammalian...
Formerly thought to be ‘junk DNA,’ microRNAs (miRNAs) are small chains of about two dozen non-coding nucleotides. They are emerging as important regulators...
An early mammal called Priacodon fruitaensis was well adapted for powerful and precise biting, and had a varied faunivorous diet that likely included insects...
Zoologists believe they have found a previously unknown species of tree hyrax in the Taita Hills, Kenya.
A female tree hyrax in Ngangao Forest, Taita Hills,...
In a study that has implications to advance medicine and biodiversity conservation, a large international consortium of researchers involved in the Zoonomia...
The fur of the platypus (Ornithorhynchus anatinus), one of only five extant species of monotremes (egg-laying mammals), absorbs ultraviolet light at wavelengths...
Paleontologists have uncovered a previously unknown species of cynodont that lived during the Triassic period in what is now Arizona, the United States.
An...
Filikomys primaevus, a new genus and species of multituberculate mammal that lived during the Late Cretaceous epoch, has been identified from multi-individual...
A new genus and species of mammaliaform that lived during the Triassic period has been identified from a partial jaw with teeth found on the eastern coast...
The Carnian Pluvial Episode, a major climate change event that occurred around 234 to 232 million years ago (Late Triassic epoch), was a time of global...
European moles (Talpa europaea) appear to avoid chewing on sand when eating earthworms because it is likely that they find the sensation as repulsive as...
Purussaurus, a top predator that lived in the wetlands of proto-Amazonia between 6 and 13 million years ago (Miocene epoch), hunted not only aquatic animals...
A team of paleontologists and mechanical and biomedical engineers has compared CT scans of the fossilized bones of hadrosaurs and other dinosaurs with...
![Ternary structure of Polθ on a DNA/RNA primer-template: (A) Polθ polymerase; (B) DNA/RNA extension by Polθ and PolθΔL; (C) structure of Polθ:DNA/RNA:ddGTP; (D) superposition of Polθ:DNA/RNA (marine) and Polθ:DNA/DNA (orange, 4x0q); the fingers and thumb subdomains undergo reconfiguration; (E) superposition of Polθ:DNA/RNA (marine) and Polθ:DNA/DNA (orange, 4x0q) highlighting a 12-Å shift of K2181 (blue box; thumb) and a 4.4-Å shift of E2246 (gray box; palm); (F) superposition of nucleic acids and ddGTP from Polθ:DNA/RNA:ddGTP and Polθ:DNA/DNA:ddGTP structures; (G) top: electron density of ddGTP and 3′ primer terminus in Polθ:DNA/RNA structure; bottom: zoomed-in image of the superposition of active sites, illustrating a different conformation of ddGTP in the Polθ:DNA/RNA (blue) and Polθ:DNA/DNA (salmon) complexes; (H) interactions between ribose 2’-hydroxyl groups of the RNA template and residues in the Polθ:DNA/RNA structure; red dashed lines, hydrogen bonds; (I) DNA/RNA used for cocrystallization with Polθ and ddGTP (top); strong electron density is present for four base pairs [nucleotides located at positions 2 to 5 (underlined) of the DNA/RNA] and two base pairs resulting from an incorporated ddGMP (2’,3’ dideoxyguanosine monophosphate) (green; position 1) and a bound unincorporated ddGTP (red; position 0) in the active site (top); interactions between Polθ and nucleic acids in Polθ:DNA/RNA:ddGTP (bottom); interactions between residues and phosphate backbone, sugar oxygen, or nucleobase are shown in blue, yellow, and green, respectively; hydrogen bonds between Polθ and ribose 2’-hydroxyl groups are indicated (boxed residues); (J) interactions between Polθ and nucleic acids in Polθ:DNA/DNA:ddGTP (4x0q); color scheme identical to (I). Image credit: Chandramouly et al., doi: 10.1126/sciadv.abf1771.](https://cdn.sci.news/images/2021/06/image_9759-Polymerase-Theta-195x110.jpg)
