new model species for evo-devo
Non-classical model systems
Among the many, sometimes contradictory, criteria that have been used for promoting model species, the most prominent has probably been their relevance for understanding human biology. Recently however, the debate has partly shifted from the search for evolutionary conservation (medicine-driven models) to a better understanding of the generative mechanisms underlying biological diversity (Evo-Devo-driven models). Integration of multiple disciplines, beyond developmental genetics and evolutionary molecular genetics, as well as of innovative technologies will help biologists to open the massive realm of living species to genome manipulation and phenotypic investigation. However, a consensual list of model species must still be reached for optimizing the interplay between in silico analyses and in vivo experiments, and we claim that the Evo-Devo community should play a more energetic role in this endeavor. The criteria that are relevant to the choice of a set of model species are multiple and can even be contradictory. We think that the only possibility is the use of a pragmatic (and partly subjective) optimisation approach, incorporating criteria such as phylogenetic position as well as number and nature of the ancestral/derived character states of the model species, level of diversity within a relevant higher taxon to which the chosen species belongs, ease with which the representative species can be handled, housed and bred, and their protection status. We have applied such an approach for a set of species that could serve as the workhorses for evo-devo research within amniotes. Using these species, we apply classical developmental and molecular genetics methods (in-situ hybridization, DNA arrays, library building and sequencing, etc.) for understanding the molecular generative mechanisms of phenotypes of interest in multiple non-classsical mammalian and reptilian model species.
Stay tuned for additional information soon.
Figure from Tzika & Milinkovitch 2008 (A Pragmatic Approach for Selecting Evo-Devo Model Species in Amniotes); see below for full reference. Right: cladogram showing the best estimate of the phylogeny of amniotes based on molecular data. Left: phylogram showing the time of divergence among major amniote lineages. Some paleontologists favour a model of radiation of placental mammals after the Mesozoic/Cenozoic boundary. Dotted lines indicate that no reliable estimate for the divergence of snakes from lizards is available. Two lineages of lizards are indicated to underline the likely paraphyly of that group (with respect to snakes). Geological eras are indicated (Paleozoic, 570-251 mya; Mesozoic, 251-65 mya; Cenozoic, 65-0 mya).
Figure: Some of the new model species we porposed for amniotes in Tzika & Milinkovitch 2008 (A Pragmatic Approach for Selecting Evo-Devo Model Species in Amniotes); see below for full reference.
1, Pelodiscus sinensis, the Chinese soft-shell turtle; 2, Pogona vitticeps, the bearded dragon; 3, Elaphe guttata, the corn snake; 4, Crocodylus niloticus, the Nile crocodile; 5, Petaurus breviceps, the sugar glider (the left and right insets show the patagium and the embryo in the mother pouch, respectively); 6, Echinops telfairi (the lesser hedgehog tenrec); 7, Atelerix albiventris, the African pygmy hedgehog.
Selected publications
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✓Tzika A.C., Ullate-Agote A., Grbic D. & M. C. Milinkovitch
Reptilian Transcriptomes v2.0: An Extensive Resource for Sauropsida Genomics and Transcriptomics
Genome Biol. Evol. 7: 1827-1841 (2015) -
✓Ullate-Agote A., Milinkovitch M.C. & A.C. Tzika
The genome sequence of the corn snake (Pantherophis guttatus), a valuable resource for EvoDevo studies in squamates
Int. J. Dev. Biol. 58: 881-888 (2014) -
✓Werneburg I., Tzika A.C., Hautier L., Asher R.J., Milinkovitch M.C. & M.R. Sanchez-Villagra
Development and embryonic staging in non-model organisms: the case of an afrotherian mammal
Journal of Anatomy 222: 2-18 (2013) -
✓Tzika A.C., Helaers R., Schramm G. & M. C. Milinkovitch
Reptilian-transcriptome v1.0, a glimpse in the brain transcriptome of five divergent Sauropsida lineages and the phylogenetic position of turtles
EvoDevo 2011, 2: 19 -
✓Milinkovitch M.C. & A. C. Tzika
Escaping the Mouse Trap; the Selection of New Evo-Devo Model Species
Journal of Experimental Zoology (Mol. Dev. Evol.) 308B: 337–346 (2007) -
✓Tzika A. C. & M. C. Milinkovitch.
A Pragmatic Approach for Selecting Evo-Devo Model Species in Amniotes
Chapter 7 Pages 119-140 in ‘Evolving Pathways; Key Themes in Evolutionary Developmental Biology’ (A. Minelli & G. Fusco, eds.), Cambridge University Press 2008 -
✓Di-Poï N., Montoya-Burgos J.I., Miller H., Pourquié O., Milinkovitch M.C. & D. Duboule
Changes in Hox genes’ structure and function during the evolution of the squamate body plan
Nature, 464: 99-103 (2010)
