Cell classes are the building blocks for the central nervous system. It is widely believed that major classes of neurons have been identified in the retina,...
While most mammals are drab browns and grays, there are a small number of well-known and intriguing exceptions. Perhaps the most famous of all is the giant...
The end-Cretaceous mass extinction 66 million years ago was characterized by a worldwide ecological catastrophe and rapid species turnover. Arboreal (tree-dwelling)...
Nearly 63% of Afro-Arabian mammalian species went extinct approximately 30 million years ago (Oligocene epoch), after Earth’s climate shifted from swampy...
An international team of researchers led by the University of Georgia has documented ultraviolet biofluorescence in live southeastern pocket gophers (Geomys...
New research shows that a signaling molecule encoded by a gene called Dickkopf 4 underlies a naturally occurring mutation that affects tabby patterns and...
Paleontologists have identified three new species of placental mammals called condylarths (archaic ungulates) from fossils found in Wyoming, the United...
A research team led by Florida Museum of Natural History scientists has compiled 140,499 body size records of over 100 North American mammals to test how...
Researchers from the University of Illinois at Urbana-Champaign and the Universidade Federal do Rio Grande do Sul have observed several bird species exhibiting...
Giraffes (Giraffa camelopardalis) exhibit many of the features typical of mammals with complex cooperative social systems and matrilineal societies, according...
An international team of scientists has retrieved and analyzed nuclear and mitochondrial environmental DNA of humans, wolfs (Canis lupus), and bisons (Bison...
Paleontologists have identified two new species of palaeotheriid mammals from fossils found at the Eocene site of Zambrana in Alava, Spain.
Palaeotheriid...
In a new study published this week in the journal Nature, an international team of researchers analyzed DNA from more than 700 sediment samples that were...
A new species of the giant rhinoceros genus Paraceratherium has been identified from the fossilized remains found in Gansu Province, northwestern China.
Life...
Dendrohyrax interfluvialis lives in the wet and dry forests that lie between the two rivers in coastal regions of southeastern Ghana, southern Togo and...
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...
![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)
