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Genome duplication, extinction and vertebrate evolution
Philip C J Donoghue1, Mark A Purnell
1Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol, UK, BS8 1RJ. phil.donoghue@bristol.ac.uk
Trends in Ecology & Evolution
|May 17, 2006
Summary
Gene or genome duplication events in vertebrate evolution do not correlate with the origin of body plans when fossil data is included. Including fossils reveals that bursts of character acquisition disappear, challenging previous hypotheses.
Area of Science:
- Evolutionary biology
- Genomics
- Paleontology
Background:
- Vertebrate evolution shows three major gene/genome duplication events linked to key innovations.
- These duplications were previously correlated with bursts of new traits and increased complexity in living species.
- This correlation was based solely on data from extant (living) taxa.
Purpose of the Study:
- To investigate the relationship between gene/genome duplication and evolutionary complexity in vertebrates.
- To determine if the correlation holds when fossil data is incorporated into phylogenetic analyses.
- To re-evaluate hypotheses linking genome duplication events to the origin of major body plans.
Main Methods:
- Comparative phylogenetic analysis incorporating both living and fossil vertebrate taxa.
- Examination of character acquisition patterns across vertebrate phylogeny.
- Assessment of morphological gaps and complexity in relation to gene/genome duplication events.
Main Results:
- When fossil data is included, bursts of character acquisition are no longer evident.
- Gene or genome duplications in vertebrate phylogeny do not correlate with the origin of body plans.
- The proposed link between genome duplication and the evolution of complexity is not supported by inclusive datasets.
Conclusions:
- The previously observed correlation between gene/genome duplication and evolutionary complexity in vertebrates is an artifact of using only living taxa.
- Incorporating fossil data refutes the hypothesis that genome duplications drove the origin of major vertebrate body plans.
- Future research should consider comprehensive datasets including fossil evidence to accurately reconstruct evolutionary patterns.
Related Concept Videos
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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.
02:31Synteny and Evolution
John H. Renwick first coined the term “synteny” in 1971, which refers to the genes present on the same chromosomes, even if they are not genetically linked. The species with common ancestry tend to show conserved syntenic regions. Therefore, the concept of synteny is nowadays used to describe the evolutionary relationship between species.
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02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
02:55The Evidence for Evolution
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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...
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02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...