MY RESEARCH
Understanding Biodiversity
THE GENETIC AND DEVELOPMENTAL BASIS OF PHENOTYPIC INTEGRATION
Adaptive radiations are characterized by extreme and/or iterative phenotypic divergence; however, such variation does not accumulate evenly across an organism. Instead, it is often partitioned into sub-units, or modules, which can differentially respond to selection. While it is recognized that changing the pattern of modularity or the strength of covariation (integration) can impact how phenotypic evolution proceeds, the genetic, developmental, and evolutionary underpinnings remain unclear. Our work examining the craniofacial skeleton of cichlids and placental mammals has uncovered roles for developmental interactions and pleiotropy in determining the structure of phenotypic integration, and has documented how differences in the strengths of integration among taxa can impact the rate and range of morphological evolution. See Smith et al. 2015, Evol. Biol.; Conith et al. 2018, Am. Nat.; Conith et al. 2020, BMC Evol. Biol.; Conith and Albertson 2021, Nat. Commun. IMAGE: A. Konings.
THE IMPACT OF GENETIC AND DEVELOPMENTAL CONSTRAINTS ON VERTEBRATE EVOLUTION
The skull is a multifunctional structure involved in feeding, communication, and housing the sensory structures, and the competing demands of all these roles are often at odds with each other. Given these many demands, traits across the skull will experience numerous trade-offs that can be developmental, genetic, or phylogenetic in nature. Our work has documented the possible origins and impacts of constraints using the marsupial-placental mammal reproductive dichotomy, the extreme fin morphologies of the Bramidae, or the craniofacial region of cichlid fishes. In many cases we find a small genetic change in the pathway regulating development of key structures can have large evolutionary consequences for the taxonomic and morphological diversity of a clade. See Conith et al. 2018, PNAS; Gilbert et al. 2021, IOB; Conith et al. 2021, Nat. Commun; Conith et al. 2021. J. Evol. Biol. IMAGE: M. Gilbert.
UNDERSTANDING THE IMPORTANCE OF HARD- AND SOFT-TISSUE INTERACTIONS THROUGH DEVELOPMENT
The shape of the craniofacial skeleton is constantly changing through ontogeny and reflects a balance between developmental patterning and mechanical-load-induced remodeling. Soft-tissues such as ligaments and muscles are a major contributor to producing the mechanical environment that is crucial for ‘normal’ skull development. Our work examining the degree of correlated development and remodeling of bone-muscle complexes in the skull demonstrated that the roles for muscular input on skeletal shape extend beyond specific points of origin or insertion, and hold significant potential to influence broader patterns of craniofacial geometry. See Conith et al. 2018, PNAS; Conith et al. 2019, Evolution; Conith et al. 2019, genesis; Conith et al. 2021, Mol. Ecol.; Conith et al. 2023, Evol. & Dev. IMAGE: A. Conith.