Tag Archives: molecular clock

Oldest existing lizard-like fossil hints at scaly origins

The fossilised remains of a reptile closely related to lizards are the oldest yet to be discovered.

Two new fossil jaws discovered in Vellberg, Germany provide the first direct evidence that the ancestors of lizards, snakes and tuatara (known collectively as lepidosaurs), were alive during the Middle Triassic period – around 240 million years ago. (more…)

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Placental Mammal Diversity Blossomed After Age of Dinosaurs

Scientists build new ‘tree of life’ for placentals, visualize common ancestor

Scientists have reconstructed the common ancestor of placental mammals–an extremely diverse group including animals ranging from rodents to whales to humans–using the world’s largest dataset of both genetic and physical traits. (more…)

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How Do Cells Tell Time? Scientists Develop Single-Cell Imaging to Watch the Cell Clock

COLUMBUS, Ohio – A new way to visualize single-cell activity in living zebrafish embryos has allowed scientists to clarify how cells line up in the right place at the right time to receive signals about the next phase of their life.

Scientists developed the imaging tool in single living cells by fusing a protein defining the cells’ cyclical behavior to a yellow fluorescent protein that allows for visualization. Zebrafish embryos are already transparent, but with this closer microscopic look at the earliest stages of life, the researchers have answered two long-standing questions about how cells cooperate to form embryonic segments that later become muscle and vertebrae. (more…)

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