Extensive dog diversity millennia before modern breeding practices

Photograph of a modern dog skull used for the photogrammetric reconstruction of 3D models in the study.
Photo Credit: C. Ameen / University of Exeter

A groundbreaking archaeological study has revealed when domestic dogs first began to show the remarkable diversity that characterizes them today. By applying cutting-edge shape analysis to hundreds of archaeological specimens spanning tens of thousands of years, researchers have traced the emergence of distinct dog forms deep into prehistory pinpointing the moment dogs began to diversify in size and shape – at least 11,000 years ago. 

These findings challenge long-standing assumptions that canine diversity is largely a recent phenomenon shaped by selective breeding which started with the Victorian Kennel Clubs. Instead, the study demonstrates that significant variation in skull shape and size among domestic dogs was already present thousands of years ago, soon after their divergence from wolves. 

How fishes of the deep sea have evolved into different shapes

The silvery color of the hatchetfish, which lives in the water column of the deep sea, provides camouflage in dimly lit portions of the ocean.
Photo Credit: Chris Martinez

Fish species living in the deep sea feature a surprisingly large range of body shapes that evolved in different ways and at different rates depending on where the fishes live in the ocean, new research shows. 

Overall, the analysis of nearly 3,000 species showed more diversity of body types among the pelagic fishes, those that swim in open water, than among the benthic species spending their life on the ocean floor. Pelagic fish body types span from the round anglerfish to skinny eels, while benthic fishes generally share a common elongated, tapered shape. 

“We found that evolution pushes and pulls fish body shape in different directions depending on whether they’re benthic or pelagic,” said lead study author Elizabeth Santos, assistant professor of evolution, ecology and organismal biology at The Ohio State University. 

“We talk about the deep sea as if it is sort of all one thing, when really it is not – it is actually quite diverse,” she said. “There are very different types of environments in the deep sea that have their own different effects on evolution.” 

Variety of animals evolved similar genetics solutions to survive on land, study finds

Transition from water to land 
Image Credit: Dinghua Yang

Animals from completely different branches of the tree of life such as insects, worms and vertebrates independently evolved similar genetic solutions to survive on land, according to a new study from researchers at the University of Bristol and University of Barcelona. 

The research, published in Nature suggests that some adaptations are so essential that environmental challenges make evolution predictable.  

The researchers decoded the genetic basis of one of evolution’s more extraordinary innovations – the transition from water to land. 

Researchers discover enlarged areas of the spinal cord in fish, previously found only in four-limbed vertebrates

Zebrafish at the Laboratory of Fish Biology in Nagoya University Researchers discovered that zebrafish have enlarged areas of the spinal cord, previously believed to exist only in four-limbed vertebrates.
 Photo Credit: Naoyuki Yamamoto

Four-limbed vertebrates, known as tetrapods, have two enlarged areas in their spinal cords. The two enlargements have a correlation with the forelimbs and hind limbs, respectively. These enlargements are thought to be caused by the complex muscular system and the rich sensory networks supplying nerves to the limbs.

Meanwhile, it was long thought that fish had no enlarged areas in their spinal cords due to the absence of limbs. However, a recent study by scientists from Nagoya University in Japan has revealed that zebrafish, in fact, have enlarged areas in their spinal cords, although these areas are not visible to the naked eye.

"We thought that fish also have spinal enlargements because they have paired pectoral and pelvic fins, which correspond to forelimbs and hind limbs in tetrapods, respectively," said  Naoyuki Yamamoto, a professor at Nagoya University's Graduate School of Bioagricultural Sciences and the lead author of the study.