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Microbead Implantation in the Zebrafish Embryo
Published on: July 30, 2015
Duplication and divergence of fgf8 functions in teleost development and evolution
Richard Jovelin1, Xinjun He, Angel Amores
1Center for Ecology and Evolutionary Biology, University of Oregon, Eugene, USA.
Summary
Fibroblast growth factor (Fgf) gene evolution reveals duplication events in ray-fin fish, leading to specialized functions in embryo development. Different Fgf genes may regulate limb development across vertebrates.
Area of Science:
- Developmental biology
- Evolutionary biology
- Genomics
Background:
- Fibroblast growth factors (Fgfs) are crucial for conserved embryonic patterning.
- Understanding Fgf evolution provides insights into vertebrate development.
Purpose of the Study:
- Identify Fgf8/17/18 subfamily members in stickleback (Gasterosteus aculeatus).
- Investigate evolutionary relationships and expression patterns of these Fgf genes.
- Explore the functional divergence of Fgf genes after duplication events.
Main Methods:
- Phylogenetic analysis of Fgf genes.
- In situ hybridization to examine gene expression patterns in stickleback embryos.
- Comparative analysis of Fgf gene expression between stickleback and zebrafish.
Main Results:
- Identified stickleback Fgf genes, renaming teleost fgf8 and fgf17a to fgf8a and fgf8b, respectively.
- Phylogenetic analysis indicates Fgf8/17/18 subfamily expansion during ray-fin fish genome duplication.
- Expression patterns of stickleback fgf8 duplicates show tissue specialization post-duplication.
- Comparative analysis suggests lineage-specific functional partitioning and gene loss/gain in Fgf8 co-orthologs.
- Differences in fgf8a expression and roles of fgf16/fgf24 in pectoral appendage development highlight functional plasticity.
Conclusions:
- The Fgf8/17/18 subfamily expanded via gene duplication in ray-fin fish, followed by subfunctionalization.
- Fgfs exhibit conserved and divergent roles in vertebrate embryonic development, particularly in limb formation.
- Comparative genomics and expression studies are essential for understanding the evolution of gene function.
Related Concept Videos
02:37Gene Duplication and Divergence
The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
01:57Gene Families
Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes are mistakenly duplicated during cell division. Unlike their parent genes (which are subject to selection pressure to maintain function), these gene copies do not need to preserve their sequences and may evolve at a relatively faster rate.
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
01:51Determination
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01:56Gastrulation
Gastrulation establishes the three primary tissues of an embryo: the ectoderm, mesoderm, and endoderm. This developmental process relies on a series of intricate cellular movements, which in humans transforms a flat, “bilaminar disc” composed of two cell sheets into a three-tiered structure. In the resulting embryo, the endoderm serves as the bottom layer, and stacked directly above it is the intermediate mesoderm, and then the uppermost ectoderm. Respectively, these tissue strata will form...
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.The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while also...