The Age of Reptiles

On the eve of the publication of the Anolis genome paper in the journal Nature, it is an exciting time to study reptile evolution. Before 2005, there were no reptile genomes available. Anolis was chosen to be the first genomic representative of an extremely diverse class of vertebrates, an account of this process is provided by Harvard University professor Jonathan Losos on his Anolis-themed blog Anole Annals.

Even though the paper will be published in 2011, the Anolis genome has been available since 2007 (it must be exceedingly difficult to write a paper with a few score plus authors), and a variety of researchers pounced on the chance to study the first reptile sequence. For instance, it has been observed that the Anolis genome lacks isochores which are common in other vertebrates (Fujita et al. 2011). We published a paper reviewing the impact of transposable elements (TEs) in the Anolis genome (Tollis and Boissinot 2011), which I synopsized in a recent post on Anole Annals.

In our paper, we discuss Castoe et al. 2011 which describes TEs found in two snake genomes, Burmese python and copperhead. There is currently a python genome project as well, and the first draft of this genome is already available. The python belongs to an ancient group of snakes and is well studied due to its ability to withstand extreme metabolic shifts as a result of the serpentine feast and famine lifestyle.

The Ed Green lab and the Genome Technology Center at UC Santa Cruz is working on the alligator genome. Alligators and crocodiles are the closest living relatives of birds, and together they form a group called archosaurs. This was a successful and diverse group during the Mesozoic Era, and extinct members include all non-avian dinosaurs and pterosaurs. The alligator genome will teach us more about this important branch of the vertebrate family tree. In addition, an alligator genome will have value to human health because of their incredibly complex and robust immune systems (they live in rank swamps and rarely get infections). More crocodilians are being sequenced as well, and their genome dynamics are an active area of research (see David Ray’s lab page at Mississippi State).

Python versus Alligator! Python already has his genome sequence available on NCBI so he wins the current battle... but who will win the war? (photo from Wikipedia)

There are several more reptiles that are either being sequenced currently or are being considered for sequencing. The painted turtle will be the first large genome (3Gb) to be sequenced fully with next-generation 454 technology. There is a proposal in place to sequence the garter snake genome as well. It won’t be long before we find ourselves in a new, genomic Age of Reptiles.

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2 Comments on “The Age of Reptiles”

  1. […] The Age of Reptiles (anolistollis.wordpress.com) […]

  2. […] was published. At the time, it was the only reptile to have a fully sequenced genome (although this list is ever growing) and the phylogenetic gap it filled among sequenced vertebrates created a real demand. In […]


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