ABSTRACT
Natural populations subjected to strong environmental selection pressures offer a window into the genetic underpinnings of evolutionary change. Cavefish populations, Astyanax mexicanus (Teleostei: Characiphysi), exhibit repeated, independent evolution for a variety of traits including eye degeneration, pigment loss, increased size and number of taste buds and mechanosensory organs, and shifts in many behavioural traits. Surface and cave forms are interfertile making this system amenable to genetic interrogation; however, lack of a reference genome has hampered efforts to identify genes responsible for changes in cave forms of A. mexicanus. Here we present the first de novo genome assembly for Astyanax mexicanus cavefish, contrast repeat elements to other teleost genomes, identify candidate genes underlying quantitative trait loci (QTL), and assay these candidate genes for potential functional and expression differences. We expect the cavefish genome to advance understanding of the evolutionary process, as well as, analogous human disease including retinal dysfunction.
Subject(s)
Characidae/genetics , Evolution, Molecular , Eye/embryology , Gene Expression Regulation, Developmental , Retina/embryology , Animals , Apoptosis , Characidae/embryology , DNA Transposable Elements , Environment , Fish Proteins/genetics , Gene Expression Profiling , Genome , In Situ Hybridization , Molecular Sequence Data , Phenotype , Quantitative Trait Loci , Retina/physiologyABSTRACT
A recent study in mice deciphers the complex genetic regulatory network underlying the morphogenesis of the face. The enhancer landscape underlying craniofacial development provides multiple entry points to understand what makes up the face, in natural variation or pathological conditions.
Subject(s)
Enhancer Elements, Genetic/physiology , Face/anatomy & histology , Gene Expression Regulation, Developmental , Maxillofacial Development/genetics , Skull/growth & development , AnimalsABSTRACT
Do new anatomical structures arise de novo, or do they evolve from pre-existing structures? Advances in developmental genetics, palaeontology and evolutionary developmental biology have recently shed light on the origins of some of the structures that most intrigued Charles Darwin, including animal eyes, tetrapod limbs and giant beetle horns. In each case, structures arose by the modification of pre-existing genetic regulatory circuits established in early metazoans. The deep homology of generative processes and cell-type specification mechanisms in animal development has provided the foundation for the independent evolution of a great variety of structures.
