Related Experiment Video
Updated: May 30, 2026
09:16
Analyzing Craniofacial Morphogenesis in Zebrafish Using 4D Confocal Microscopy
Published on: January 30, 2014
Craniofacial divergence and ongoing adaptation via the hedgehog pathway
Reade B Roberts1, Yinan Hu, R Craig Albertson
1Department of Biology, University of Maryland, College Park, MD 20742, USA.
Summary
Genetic variation in the Patched1 (Ptch1) gene drives adaptive changes in cichlid fish jaw shape. This evolution of jaw morphology influences feeding strategies and contributes to speciation in Lake Malawi cichlids.
Area of Science:
- Evolutionary biology
- Genetics
- Ichthyology
Background:
- Adaptive variation in craniofacial structure is crucial for resource specialization and speciation.
- The genetic basis of craniofacial adaptation, particularly in fish, is not well understood.
Purpose of the Study:
- To identify the genetic loci responsible for adaptive variation in craniofacial structure.
- To investigate the role of specific genes in the evolution of feeding morphology in cichlid fish.
Main Methods:
- Analysis of genetic variation in the Patched1 (Ptch1) gene in Lake Malawi cichlid fish.
- Correlating Ptch1 alleles with craniofacial morphology, specifically the retroarticular (RA) process length and jaw mineralization.
- Examining Ptch1 allele frequencies across different cichlid genera and species with varying feeding ecologies.
Main Results:
- Alleles of the Patched1 (Ptch1) gene are responsible for adaptive variation in lower jaw shape in cichlids.
- A derived Ptch1 allele is associated with a reduced RA process, enhancing suction-feeding speed.
- An alternate Ptch1 allele correlates with a longer RA process and robust jaw mineralization, indicative of biting feeding strategies.
Conclusions:
- Ptch1 gene polymorphism underlies both macroevolutionary divergence among cichlid genera and microevolutionary fine-tuning within species.
- This genetic variation in craniofacial morphology, mediated by Ptch1, likely drives niche partitioning and ecological speciation in cichlid fishes.
- The hedgehog pathway receptor Patched1 (Ptch1) is a key genetic factor in the adaptive radiation of cichlid fishes.
Related Concept Videos
02:33Hedgehog Signaling Pathway
The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...
02:33Hedgehog Signaling Pathway
The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...
01:30Neurulation
Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three primary cell layers of the embryo: ectoderm, mesoderm, and endoderm. In humans, the majority of this system is formed via primary neurulation, in which the central portion of the ectoderm—originally appearing as a flat sheet of cells—folds upwards and inwards, sealing off to form a hollow neural tube. As development proceeds, the anterior...
01:51Determination
During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. Specification is demonstrated by removing a segment of an early embryo, “neutrally” culturing the tissue in vitro—for example, in a petri dish with simple medium—and then observing the derivatives. If the cultured region gives rise to cell types that it would normally generate in the embryo, this means that it is specified. In contrast, determination...
03:14Notch Signaling Pathway
The Notch signaling pathway is a major intracellular signaling pathway that is highly conserved over a broad spectrum of metazoan species. It stands unique from other intracellular signaling mechanisms in animals because notch protein itself acts as the receptor as well as the primary signaling molecule.
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
01:54Convergent Evolution
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.