Extinct fossils reveal their genetic pattern

Oct 23, 2012

Researchers have provided a glimpse at genetic expression in long-extinct fossil dinosaurs. This new insight comes from the discovery of a correlation between the genetic patterning observed in today's chickens and crocodiles, and the pattern of different bone shapes along their spines. For the first time a direct correlation between the genetic expression and morphological variation is identified.

Integrating fossil and genetic data to understand the evolution of life has gained importance over the past two decades. Previously, this approach has been limited to using development of individuals to infer an interpretation of the evolution of . Here, the direct correlation between gene expression and provides new insight on the genetic basis of evolution in extinct dinosaurs and their relatives.

Homeotic genes or Hox genes choreograph the development and patterning of structures from the head to the tail in metazoan animals. In vertebrates, the central function of these genes is visible in the patterning of the vertebral column. "It has been proposed that a unique spatiotemporal pattern of specifies differing vertebral morphologies," says Christine Böhmer, lead researcher of the study at the Ludwig-Maximilians-Universität and the Bavarian State Collection for Palaeontology and Geology in Munich, Germany.

Most mammals have seven cervical vertebrae, irrespective of the neck length. For example, giraffes and mice both possess seven neck bones or vertebrae. In contrast, amphibians, reptiles and birds have a highly variable numbers of . Crocodiles have nine neck vertebrae, and swans with their long necks even have 25 neck vertebrae. "As far as we know the genetic code is the same for mammals, but in archosaurs (crocodiles, birds and their relatives) there is that correlates with the vertebral morphology," says Böhmer. The idea of morphology-specific Hox gene patterning was tested using chicken and crocodile embryos, and the results were applied to fossil species.

In a paper presented at the Society of Vertebrate Paleontology annual meeting, the researchers first use molecular methods to establish the Hox pattern of living crocodiles and chickens. The researchers then tested for correlations between the Hox gene pattern and bone shape. These insights were applied to sauropod dinosaurs, an iconic fossil group with highly variable vertebral number and morphology. This approach identifies subregions in the neck of the extinct dinosaurs that result from specific expansions of Hox gene activity.

Explore further: New insights into how different tissues establish their biological and functional identities

Related Stories

The skeleton: Size matters

Oct 27, 2009

Vertebrates have in common a skeleton made of segments, the vertebrae. During development of the embryo, each segment is added in a time dependent manner, from the head-end to the tail-end: the first segments to be added ...

Human-like spine morphology found in aquatic eel fossil

May 23, 2012

For decades, scientists believed that a spine with multiple segments was an exclusive feature of land-dwelling animals. But the discovery of the same anatomical feature in a 345-million-year-old eel suggests ...

Recommended for you

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.