Our research focuses on innovations and mechanisms that facilitate or constrain evolutionary changes of body plans . We want to understand questions such as: Why do we have two eyes, two lungs, four limbs and seven neck vertebrae. To understand this, we study both why such traits can hardly ever change in evolution and why, exceptionally, changes are possible. Our data have implications for biodiversity, human morbidity and lethality.
Body plan evolution, developmental constraints, phylotypic stage, vertebral column, digits, human evolution, Evo-Devo, regeneration, parthenogenesis, cichlids, phenotypic plasticity, cognitive science
- Conservation of phylotypic stages
- Conservation of the number of seven neck vertebrae in mammals
- Why is the number of trunk vertebrae variable in slow mammals, but conserved in fast ones, including humans
- Evolution of digit numbers
- Developmental constraints against parthenogenesis
Why do almost all mammals have seven cervical vertebrae? The mammalian vertebral column is highly variable, reflecting adaptations to a wide range of lifestyles. However, the number of neck vertebrae is surprizingly constant. Variations occur within humans, but almost only in individuals that die before birth or as neonate (~90% is dead around birth). The number variations themselves are usually not problematic, but they are strongly associated with harmful side-effects, including congenital abnormalities of all organ systems. There is, therefore strong selection against individuals with abnormal numbers. After birth there is further selection because of an increased incidence of paediatric tumors and lower fertility. Data on other mammals support an association of the number variations with congenital abnormalities. Exceptionally the super slow sloths and manatees can tolerate many of the normally deleterious side-effects, which has apparently allowed them to evolve abnormal cervical vertebral numbers.
Photographs: Joris van Alphen
Developmental constraints-Phylotypic stages-Evolution and development of the vertebral column-Evolution and development of digits-Phenotypic plasticity-Parthenogenesis-Regeneration
- Galis F., Metz J.A.J., van Alphen J.J.M. 2018. Development and evolutionary constraints. Ann. Rev. Ecol. Evol. Syst. 49:499-522
- van der Geer, A.A.E., Galis F., 2017. High incidence of cervical ribs indicates vulnerable condition in Late Pleistocene woolly rhinoceroses. PeerJ 5:e3684 https://doi.org/10.7717/peerj.3684
- Galis F., Carrier DR, van Alphen J, van der Mije SD, Van Dooren TJ, Metz JA, ten Broek CM. 2014. Fast running restricts evolutionary change of the vertebral column in mammals. Proc. Natl. Acad. Sci. U. S. A. 111: 11401-06
- Ten Broek C.M.A., Bakker A.J., Varela-Lasheras I., Bugiani M., Van Dongen S., Galis F. 2012. Evo-devo of the human vertebral column. On homeotic transformations, pathologies and prenatal selection. Evol. Biol. 39:456-471
- Varela-Lasheras, I., Bakker A.J., van der Mije S.D., Metz J.A.J., Van Alphen J., Galis F. 2011. Breaking evolutionary and pleiotropic constraints in mammals. On sloths, manatees and homeotic mutations. EvoDevo 2011, 2:11
- Galis, F., Arntzen J.W., Lande R., 2010. Dollo’s law and the irreversibility of digit loss in Bachia. Evolution 64, 2466-2476
- Galis, F., van der Sluijs, I., van Dooren, T.J.M., Metz, J.A.J., Nussbaumer, M. (2007). Do large dogs die young? J. exp. Zool. B. 308:119-126.
- Galis, F., G.P. Wagner, and E. Jockusch (2003). Why is limb regeneration possible in amphibians but not in reptiles, birds and mammals? Evol. and Devel. 5, 208-220.
- Galis, F., 2001. Key innovations and radiations. In: The character concept in Evolutionary Biology. Ed. G.P. Wagner. Academic Press. London.
- Galis, F., van Alphen J.J.M, and J.A.J. Metz (2001). Why five fingers? Evolutionary constraints on digit numbers. Trends Ecol. Evol.16, 637-646.
- Galis, F. and J.A.J. Metz (2001). Testing the vulnerability of the phylotypic stage: on modularity and evolutionary conservation. J. Exp. Zool. (Mol. Dev. Evol.) 291, 195-204.
- Galis, F. 1999. Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes and Cancer. J. exp. Zool. (Mol. Dev. Evol.) 285: 19-26.
- Galis, F. & E.G. Drucker, 1996. Pharyngeal biting mechanics in centrarchid- and cichlid fishes: Insights into a key evolutionary innovation. J. Evol. Biol. 9: 641-670.
- Galis, F. 1996. The application of functional morphology to evolutionary studies. Trends Ecol. Evol. 11 (3): 124-129.