The Opposing Thumb

An opinionated digit leafs through the biological literature
Media Roundup

Walking Fish & Chicks With Tails

I still remember my disappointment as a kid when, after taking me to see Raiders of the Lost Ark, my father explained to me that destroying thousand-year-old temples to get one gold statue wasn’t what archeologists normally did. The memory surfaced in my mind last week when I had a conversation with McGill University’s Hans Larsson. Dr Larsson, a paleontologist, was in Lisbon for the PhD thesis defense of IGC doctoral candidate Rui Castanhinha (also on the jury was the doyenne of French embryology, Nicole Le Douarin). Dr Larsson agreed to be interviewed for a podcast to be aired next spring, as part of set we are producing with a few of our guests.

Dr Larsson’s group in Montreal has produced many interesting fossil finds- the kind you would expect from a successful paleontology team. Where they depart the mainstream of the discipline is in their experimental approach with living species. “I became a little bit dissatisfied with just pure paleontology. It seemed too much like going out and collecting something, adding it to the museum drawer, and not actually testing anything“, Larsson told Wired in 2011. In one high-profile project with veteran dinosaur hunter (and Jurassic Park technical consultant) Jack Horner, Dr Larsson is tinkering with avian embryos to produce ancestral traits- birds as every school kid now knows, are essentially feathered dinosaurs. The quest to make “chickensaurus” is ongoing, resurrecting characters like an extended tail by altering the timing of gene expression. Larsson and lead author Emily Standen reached even further into the past, to understand how vertebrates left the oceans and invaded land habitats. To do this, they raised fish from the genus Polypterus, a group of African lungfish, entirely on land for 8 months (lungfish live up to their name and are capable of breathing out of water). The fish became more and more adept at, there’s not other way to put it, walking. The fascinating thing is this extended dry period also left Polypterus with anatomical adaptations- changes to it’s skeletal structure that mimic some aspects of the evolutionary shift from water to land.

The path from this developmental plasticity to longterm term change reflected in new lineages that radiate out into different environments is one of the most exciting areas of biology today. Interspersed with these stories of making pet dinosaurs or training walking fish, Dr Larsson shared with us tales from the field that pretty much require their own John Williams score– whether it’s collecting fossils in the Sahara during a civil war or trying to keep a plane from sinking into the Canadian High Arctic’s melting permafrost, this is not a podcast you’ll want to miss.

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