Related Concept Videos
01:15Teeth
The formation of teeth, also known as odontogenesis, is a complex process that begins in utero, around the sixth week of embryonic development. There are three stages to this process: the bud stage, the cap stage, and the bell stage.
In the bud stage, the tooth germ (an aggregation of cells) starts to form in the developing jawbone. During the cap stage, the tooth germ differentiates into enamel organ, dental papilla, and dental sac, which will later develop into the tooth's enamel, dentin and...
In the bud stage, the tooth germ (an aggregation of cells) starts to form in the developing jawbone. During the cap stage, the tooth germ differentiates into enamel organ, dental papilla, and dental sac, which will later develop into the tooth's enamel, dentin and...
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...
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.
01:21Tooth Anatomy
The human tooth enables us to eat a variety of foods, speak clearly, and even aid in shaping our faces. Teeth are composed of various elements that work together. Here's a detailed look at the anatomy of a human tooth.
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or grinding food.
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or grinding food.
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
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.The collection of fossils within sedimentary rocks give a record of common ancestry and often depicts the history of evolution.
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Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface
Published on: July 10, 2014
Amelogenin evolution and tetrapod enamel structure.
Frontiers of Oral Biology
|October 16, 2009
Summary
Researchers analyzed novel amphibian amelogenins, finding non-mammalian versions are shorter and have fewer repeats than mammalian amelogenins. This suggests sequence differences are key to complex mammalian enamel structure.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Developmental Biology
Background:
- Amelogenins are crucial proteins in tooth enamel formation.
- Understanding amelogenin diversity aids in comprehending enamel evolution.
Purpose of the Study:
- To clone and sequence novel amphibian amelogenins.
- To compare amphibian amelogenins with mammalian counterparts.
- To investigate evolutionary differences in amelogenin structure.
Main Methods:
- Cloning and sequencing of amelogenin genes from three amphibian species.
- Bioinformatic analysis of sequence data.
- Comparative sequence analysis between mammalian and non-mammalian amelogenins.
Main Results:
- Four novel amphibian amelogenin sequences were identified from three species.
- Non-mammalian amelogenins are generally shorter than mammalian ones.
- Amphibian amelogenins exhibit reduced proline content and shorter polyproline repeats.
Conclusions:
- Significant sequence variations exist between mammalian and non-mammalian amelogenins.
- Unique mammalian amelogenin features may facilitate complex enamel prism formation.
- These findings offer insights into the evolution of dental structures.