Deconstructing the long-standing a priori assumption that serial homology generally involves ancestral similarity followed by anatomical divergence
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Deconstructing the long-standing a priori assumption that serial homology generally involves ancestral similarity followed by anatomical divergence
It has long been assumed that the homologous series of ancestrally are polysomerism resulting from the “duplicate” or “repetition” of the form-and then often stray-anisomerism, for example, because they are adapted to perform different tasks as well as the forelimbs and hind legs of man. However, assuming that, with important implications for comparative biology, evolution, and development, and for evolutionary developmental biology, have generally not been thoroughly tested with extensive analysis of existing empirical data.
Perhaps not surprisingly, comparative anatomy newer, as well as knowledge of the molecular how, for example, the structure of the appendicular serial patterned along with areas anteroposterior different body axis of bilateral animals, and how “homologous” pattern forming domain is not always marked as “homologous” domain morphology, placing in question this paradigm.
In fact, in addition to showing that a lot of so-called “homologous series” perhaps not at all, recent work suggests that at least some cases of several “serial” structure is more similar to each other in the taxa derived from the phylogenetically more ancestors, as shown by authors such as Owen. In this article, we take a step back to the question of whether these assumptions are really true at all, in the first place.
In particular, we review another case called “homologous series” like the wings of insects, arthropods walk complementary, dipteran chest hair, and spine, ribs, teeth, myomeres, feathers and animal hair chordate. We show that: (a) there is almost never the case in common ancestral right; (B) in the evolution, structure-for like for example, vertebra-and / or subparts-for their example, “transverse processes” -many times to show a trend toward less in common, while in many others to show a trend toward more common, that is, one can not say that there is a clear overall trend to anisomerism.
Deconstructing the long-standing a priori assumption that serial homology generally involves ancestral similarity followed by anatomical divergence
The Tuatara genome reveals evolutionary ancient features amniote
The Tuatara (Sphenodon punctatus) -the only living members of the order of reptiles rhynchocephalia (Sphenodontia), once widespread throughout Gondwana1,2-is iconic species endemic to New Zealand2,3. A key link for the now-extinct reptile stem (from which dinosaurs, modern reptiles, birds and mammals evolved), tuatara provide key insights into amniotes2,4 ancestors.
Here we analyze the genome of the tuatara, which-about 5 Gb-is one of the largest of the unassembled vertebrate genomes. Our analysis of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analysis showed that the tuatara descent deviated from the snakes and lizards around 250 million years ago. this lineage also showed a moderate rate of molecular evolution, with examples punctuated evolution.
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Our analysis of the genome sequence to identify expansion protein, non-protein-coding RNA families and repeat elements, the latter of which shows a mixture of reptilian and mammalian features. Tuatara genome sequencing provides a valuable resource for in-depth comparative analysis of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both technical challenges and cultural obligations related to genome sequencing. Analysis of the codon usage bias (CUB) is very important in perceiving the knowledge of molecular biology, the discovery of new genes, designing transgenes and gene evolution.
