Month: September 2022

GENE REACTIVATION. “Whereas the GLO gene mutations in fish, anthropoid primates and guinea pigs are irreversible, some of the GLO pseudogenes found in bat species have been shown to be reactivated during evolution. The same phenomenon is thought to have occurred in some Passeriformes bird species.” https://lnkd.in/d66RD9Z View in LinkedIn

PRODUCTIVE ORGAN SWITCHES. “Interestingly, the vertebrate organ used to synthesize vitamin C changed twice from the kidney to the liver during evolution, once in birds and once in mammals. Whereas vitamin C is produced by the kidneys of fishes, amphibians, reptiles, and older bird orders, it is produced by the liver of more recent bird orders and of mammals.” https://lnkd.in/d66RD9Z View in LinkedIn

ORGAN SIZE. “This switch to a larger organ in more active species has been interpreted as being the result of selective pressures to maintain biochemical homoeostasis under more stressful conditions. This is reflected by the fact that the human daily recommended intake for vitamin C (60 mg) is the highest among all vitamins.” https://lnkd.in/d66RD9Z View in LinkedIn

FISH SYNTHESIS. “It has now been established that all cartilaginous and non-teleost bony fish species are able to synthesize vitamin C and that no teleost fish species can do so. The ability to synthesize vitamin C has been observed in hagfish, lampreys, sharks, rays, lungfish, coelacanths, sturgeons and bowfins, among others, but never in any of the numerous teleost fish species which have been studied.” https://lnkd.in/d66RD9Z View in LinkedIn

FISH MUTATION DATE. “This demonstrates that vitamin C synthesis is an ancestral trait of vertebrates and that it was lost in the common ancestor of teleost fish. Since several ancestral actinopterygian fish species synthesize vitamin C, this mutation must have occurred some 200 to 210 MYA.” https://lnkd.in/d66RD9Z View in LinkedIn

THREE LINEAGE LOSSES. “Vitamin C synthesis is also an ancestral trait of mammals and that this trait has been lost in three mammalian lineages: bats, guinea pigs and anthropoid primates. In contrast with teleosts fish species, the genomes of anthropoid primates and guinea pigs still contain sequences similar to GLO gene sequences, although they are highly mutated and do not code for a functional L-gulono-γ-lactone oxidase protein.” https://lnkd.in/d66RD9Z View in LinkedIn

EXON LOSSES. “The GLO gene of anthropoid primates has lost seven of the twelve exons found in functional vertebrate GLO genes, whereas the guinea pig has lost its first and fifth exon as well as part of its sixth exon.” https://lnkd.in/d66RD9Z View in LinkedIn

CONSERVED GENE REACTIVATION. “Given the currently accepted phylogeny of bats, these results therefore conclusively demonstrate that inactive genes can be reactivated during evolution. Such reactivation is made possible by the fact that the sequence of these two GLO genes is very well conserved relative to that of other mammalian species.” https://lnkd.in/d66RD9Z View in LinkedIn

TWEEKS TO REACTIVATE. “Therefore, reactivation likely only requires mutations in sites involved in the regulation of the expression of these genes. The fact that the activity level of these two genes is less than that of mice suggests that additional mutations would be necessary to further increase their expression.” https://lnkd.in/d66RD9Z View in LinkedIn

BAT GLO GENES. "Given the nature of the mutations found in the gene of this species, it could represent an example of a gene which could not be reactivated during evolution because too many reversions would be required.” https://lnkd.in/d66RD9Z View in LinkedIn