Tegu Lizard Genome Sequenced

An international team of researchers from Germany and the United States has sequenced the genome of the giant tegu (Salvator merianae), also known as the black and white tegu, a South American lizard with its own heating system.

The giant tegu (Salvator merianae). Image credit: Renato Recoder.

“Most reptiles are not able to control their body temperature like mammals do and instead must rely on its environment to attain an optimal body temperature,” said team leader Dr. Michael Hiller of the Max Planck Institute for Molecular Cell Biology and Genetics in Germany and co-authors.

“The tegu, however, has taken a step towards being full-blown warm-blooded — this lizard can raise its own body temperature by up to 10 degrees Celsius above its surroundings.”

“Although it is a native of South American rain forests and savannas, the charismatic nature of the tegu — and that it can even achieve some level of house training — makes it an extremely charming pet that is much beloved by reptile aficionados.”

“Unfortunately, international trade is one of the primary reasons that species enter new environments where they can become a menace to the native species.”

“Given the tegu’s unique biological characteristics and its potential peril to the environment, the availability of an extremely high-quality genome sequence of this large lizard serves as a rich resource for identifying and analyzing the underlying molecular basis of these aspects.”

To accomplish this, Dr. Hiller and colleagues used state-of-the-art technology to read the tegu’s DNA and assemble its genome sequence.

The newly-released tegu genome sequence is more than two billion DNA letters long and contains 22,413 coding genes, of which 16,995 (76%) likely have human orthologs.

“Similar to other reptiles, a large portion of the tegu genomes consists of repetitive sequences, which occur many times in the genome,” the researchers said.

“Repeats are a main problem when assembling a genome, especially when repeats are longer than the length of the sequenced DNA fragments, which results in gaps (breaks) in the assembly.”

“It is the most complete assembly of any reptile genome so far and will also aid us to study other lizards and snakes,” they concluded.

The results appear in the journal GigaScience.

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Juliana G. Roscito et al. The genome of the tegu lizard Salvator merianae: combining Illumina, PacBio, and optical mapping data to generate a highly contiguous assembly. GigaScience, published online November 27, 2018; doi: 10.1093/gigascience/giy141