BMS 270 Mechanisms Underlying Morphological and Physiological Diversity in Evolution and Disease (2020)

Module: 2

Sponsoring Program: BMS/DSCB/Tetrad
Administrator: Priscilla Pereira

STUDY LIST INFORMATION
Course Number: BMS 270/DSCB 270/Biochem 210
Course Name: Mechanisms Underlying Morphological and Physiological Diversity in Evolution and Disease
Units: 3
Grading Option: S/U
Course Director: Licia Selleri

MORE COURSE INFORMATION
Additional Course Director(s):  Alex Pollen
Other faculty: Guo Huang
Date: April 20 - May 8
Schedule: Mon, Wed, Fri, 1:00-3:15p
Maximum Class Size: 12
This Minicourse will be offered online. Instructions for ZOOM meetings will be sent by the course director.

Course Description: Modern evolutionary developmental biology, or evo-devo, has led to remarkable advances in our understanding of the patterns of evolutionary diversification that underlie Darwin's “endless forms” of animal life on earth. A half-century ago, it appeared unlikely that diversification of a single ancient and highly conserved tool kit of genes could provide the basis for the evolution of morphology throughout the animal kingdom. It also seemed improbable that the set of developmental genes in a fly or a worm would share many features with the genes of our species. Evo-devo research is uncovering how the evolution of form is largely about ‘teaching old genes new tricks’, to use Sean Carroll's expression (1). This underscores how the regulatory machinery that controls spatiotemporal gene expression in development primarily drives evolutionary changes. Many developmental genes encode transcription factors that regulate the activity of target genes, often via interactions with other transcription factors. The resulting complex genetic regulatory networks drive cell fate specification, differentiation, and growth. And while there are taxonomically restricted genes that contribute to organismal development, a tool kit of highly conserved genetic pathways controls the majority of morphogenetic processes throughout the animal kingdom.

Development is central to the evolution of form because it translates genotypes into morphologies. Mutations and genetic variation are the substrates for evolution. Building on genetic variation, the developmental processes of morphogenesis generate the variation in form that is then screened by natural selection to yield organisms adapted to their environment. The field of evo-devo aims to unravel the puzzle of how this ancient genetic tool kit has been employed via the evolution of complex regulatory machineries to build a striking variety of animals with disparate morphologies. This architecture of development, when coupled with the processes of natural selection and evolution, accounts for the formidable range of morphologies exhibited by biodiversity on earth.

The Minicourse will illustrate basic principles of the evolutionary origins of complex vertebrate traits. Such complex traits include, for example, elaboration of brain structure and connectivity, neural crest and placodal derivatives, and the development of craniofacial structures, which are regarded as vertebrate innovations because of their absence outside the vertebrate subphylum. The Minicourse will also cover QTL mapping and genetic architecture of evolutionary differences, as well as the genetic regulatory changes that underlie the emergence of morphological innovations. These likely facilitated the evolution and radiation of vertebrates on earth. In addition, we will discuss enhancer biology, epigenomic landscapes, and regulatory changes underlying morphological diversity in different species. The Minicourse will place special emphasis on drawing parallels between variation of form in evolution and pathological variation of form in congenital birth defects. Another theme covered will be divergent organ regenerative potential and physiological capabilities in both ontogeny and phylogeny. Phenomena of extreme biology in different species, including humans, and possible underlying molecular mechanisms will be presented and discussed.

The Minicourse will consist of 10 sessions. Each session will comprise a lecture of 50 minutes, followed by a student-led discussion of a relevant paper for an additional hour. The last session will consist of a student-led debate of 2 hours. Possible themes of the debate will revolve around driving forces of evolution, e.g. is evolution driven by coding or regulatory changes; is tissue regeneration driven by cell proliferation or by apoptosis, or by increased cell migration towards the area of injury, or by dedifferentiation of mature cells into stem cell-like precursors?

(1) Sean B. Carroll. Endless Forms Most Beautiful: The New Science of Evo Devo. 2005. W.W. Norton and Company, London, UK