Taxonomy term

genomics

Denisovan DNA found in modern Pacific Islanders, ancient Spaniards

In the time that Homo sapiens and Neanderthals were coexisting — and interbreeding — there was at least one more human species on the landscape, the Denisovans. First identified from a 41,000-year-old finger bone found in a cave in Siberia, the Denisovans are now thought to have been widespread around Eurasia. In two new studies, scientists have shed additional light on the relationship of Denisovans to other humans, finding new traces of Denisovan DNA in ancient and modern genomes.

23 Jul 2016

A long layover on the Bering land bridge

About 11,500 years ago, two infants were laid to rest side by side in a shallow grave 80 kilometers southeast of what is now Fairbanks, Alaska. The area was once part of Beringia, a strip of ice-free land connected to Asia during the last ice age. Researchers found the remains in 2013, and have now sequenced the complete mitochondrial genomes of the two children. The results revealed that the infants had different mothers and that their genetic signatures are found today throughout North and South America.

23 Mar 2016

Land plants came prepared for terrestrial life

Plants colonized land between 450 million and 420 million years ago, and, once there, they drastically altered terrestrial landscapes and provided resources for animals leaving the oceans around the same time. One adaptation that helped plants gain a foothold on land is a symbiosis with fungi known as arbuscular mycorrhizae (AM), which help plants acquire water and key nutrients from the soil and are still associated with most land plants today. In return, plants provide the fungi with bioavailable carbon produced during photosynthesis. When this symbiosis evolved has remained unclear, but researchers recently discovered that it likely has roots in a group of freshwater algae ancestral to land plants.
 
22 Jan 2016

Tree of life reshaped

Since the 1970s, the classic “tree of life” taught in classrooms has portrayed three domains of life — Archaea, Bacteria and Eukaryota — all descending from an unknown common ancestor. But behind the scenes, this textbook picture has been shifting. Many scientists now think the tree’s deepest root lies within the bacteria; and, even more recently, some have begun suspecting that the Eukaryota — including all animals, plants, fungi, slime molds and other organisms whose cells have nuclei — are actually an offshoot from the Archaea, paring the tree from three to two domains. Now, a new study furthers that claim, and with the help of a novel technique for parsing phylogenetic data in greater detail than ever before, suggests a revised backstory for the Archaea — and, by extension, us.
 
21 Oct 2015

Kennewick Man related to modern Native Americans

After two decades of controversy surrounding the origins of Kennewick Man — a 9,000-year-old skeleton found on the banks of the Columbia River in Washington state — a genomic analysis has revealed that he was, in fact, related to modern Native Americans. The 1996 discovery of the well-preserved skeleton led to a protracted legal battle among scientists, Native American tribes and the federal government over the disposition of the remains, and sparked a scientific debate about the origins of the first Americans. 
 
11 Oct 2015

Snake forebear had two back legs but no front legs

The more than 3,400 species of snakes alive today may have descended from one ancestor that lacked forelimbs, but which had small vestigial hind limbs complete with ankle bones and toes, according to a new study published in BMC Evolutionary Biology.
 
30 Aug 2015

Bird genomes untangle branches of avian family tree

Birds, the only surviving descendants of dinosaurs, have one of the most fascinating — and perplexing — family trees in the animal kingdom. To sort it out, an international collaboration known as the Avian Phylogenomics Project has sequenced the genomes of dozens of different bird species, representing all the orders in the bird family. Even with a glut of new data, however, many questions remain about the branches of the avian family tree.

 
22 Apr 2015

Benchmarks: July 11, 1997: Neanderthal DNA unraveled

On July 11, 1997, six scientists announced they had sequenced DNA from a Neanderthal fossil. It was the first time anyone had analyzed the genetics of an extinct hominin, and the findings gave paleoanthropologists a new perspective on Neanderthals’ place in the human family tree.
The team, led by Svante Pääbo, then at the University of Munich in Germany, recovered the DNA from an upper arm bone. The bone was part of a collection of fossils discovered in 1856. Quarrymen working in the Feldhofer Cave in Germany’s Neander Valley found 16 bone fragments — including a skullcap, ribs, arms, legs and part of a hip — from several different individuals. The bones resembled human bones, but there were some striking differences: The skull had pronounced brow ridges and a low, sloping forehead, and the limb bones were extraordinarily thick.
11 Jul 2010