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In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function.. Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [1]
Arrows show the vestigial structure called Darwin's tubercle. In the context of human evolution, vestigiality involves those traits occurring in humans that have lost all or most of their original function through evolution. Although structures called vestigial often appear functionless, they may retain lesser functions or develop minor new ones.
The gene sequence often remains, but is inactive. Such an unused gene may remain in the genome for many generations. [4] [7] As long as the gene remains intact, a fault in the genetic control suppressing the gene can lead to it being expressed again. Sometimes, the expression of dormant genes can be induced by artificial stimulation.
Sometimes used interchangeably with genetic variation. The total number of genetic traits or characteristics in the genetic make-up of a population, species, or other group of organisms. It is often used as a measure of the adaptability of a group to changing environments. Genetic diversity is similar to, though distinct from, genetic variability.
However, genetic and family studies have demonstrated that the presence of Darwin's tubercle may be more likely to be influenced by one's environment or developmental accidents than it is by genetics alone. [11] [12] [5] There is no clear argument for whether the trait has significance in sexual dimorphism studies or age related studies. In ...
For gene duplication events, if a gene in an organism is duplicated, the two copies are paralogous. They can shape the structure of whole genomes and thus explain genome evolution to a large extent. Examples include the Homeobox genes in animals. These genes not only underwent gene duplications within chromosomes but also whole genome ...
Homoplasy can arise from both similar selection pressures acting on adapting species, and the effects of genetic drift. [2] [3] Homoplasy is the similarity in a feature that is not parsimoniously explained by descent from a common ancestor. Most often, homoplasy is viewed as a similarity in morphological characters.
Genetic fragments such as pseudogenes, regions of DNA that are orthologous to a gene in a related organism, but are no longer active and appear to be undergoing a steady process of degeneration from cumulative mutations support common descent alongside the universal biochemical organization and molecular variance patterns found in all organisms ...