Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2025
Erindi/veggspjald / Talk/poster E43
Höfundar / Authors: Adam Ray Smith, Abbi Elise Smith, Íris Ósk Halldórsdóttir, Gunnhildur Erla Árnadóttir, Sara Rut Huldudóttir, Sara Sigurbjörnsdóttir
Starfsvettvangur / Affiliations: Háskóli Íslands
Kynnir / Presenter: Adam Ray Smith
Hedgehog (HH) signalling plays an important role in body plan development. Teleost phenotypic diversity is marked by repeated and independent evolution of craniofacial characteristics and body elongation. These traits are both highly influenced by HH signalling pathways, which raises the possibility that genes in these pathways could be associated with teleost biodiversity. In order to determine how key components of the HH pathway have evolved, we focused on two genes: (i) the smoothened (smo) receptor gene and (2) the gli transcription factors. We used blastp to identify candidate loci in a variety of genomes distributed across the teleost evolutionary tree, with a focus on lineages that have experienced dramatic diversifications in head and body shape. Using both branch and codon-based selection tests, we identified repeated and independent examples of diversifying selection across smo, gli1 and gli2. As we predicted, duplicate smo loci are not retained while de novo duplications of gli paralogs have occurred independently and repeatedly. This finding is consistent with qualitatively different evolutionary patterns and suggests that smo in particular may retain a high level of dose sensitivity as a single copy gene. This potential dosage sensitivity was supported by abnormal developmental and adult phenotypes in heterozygotic individuals of a Danio rerio knockout smo strain that had been previously reported to have normal morphologies.