Month: September 2022

“VITAMIN C (ascorbic acid) plays important roles as an anti-oxidant and in collagen synthesis. These important roles, and the relatively large amounts of vitamin C required daily, likely explain why most vertebrate species are able to synthesize this compound.” https://lnkd.in/d66RD9Z View in LinkedIn

LOST VITAMIN C SYNTHESIS. “Surprisingly, many species, such as teleost fishes, anthropoid primates, guinea pigs, as well as some bat and Passeriformes bird species, have lost the capacity to synthesize it.” https://lnkd.in/d66RD9Z View in LinkedIn

LOST VITAMIN C SYNTHESIS. “Surprisingly, many species, such as teleost fishes, anthropoid primates, guinea pigs, as well as some bat and Passeriformes bird species, have lost the capacity to synthesize it.” https://lnkd.in/d66RD9Z View in LinkedIn

BROKEN GENES. "Other historical markers can be found in our genes. We have a gene to make Vitamin C but, unfortunately for those sailors who died from scurvy, it is broken, so we have to get Vitamin C from our food. Chimpanzees and orangutans have the same broken gene, which can only have been inherited from our common ancestor for whom it was functional, as it still is for many animals." https://lnkd.in/d8JdtZG View in LinkedIn

VITAMIN FAILURES. “Humans cannot synthesize vitamins A, B1 (thiamine), B2 (riboflavin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), B12 (cobalamin), E and K but are able to synthesize some vitamin B3 (niacin) and D. The last vitamin required by humans, vitamin C (ascorbic acid), is a special case in that this organic compound is synthesized by the large majority of vertebrate and invertebrate species.” https://lnkd.in/d66RD9Z View in LinkedIn

BROKEN PATHWAY. “Gulonolactone oxidase deficiency. The non-functional gulonolactone oxidase pseudogene (GULOP) was mapped to human chromosome 8p21 that corresponds to an evolutionarily conserved segment on either porcine chromosome 4 (SSC4) or 14 (SSC14). GULO produces the precursor to ascorbic acid, which spontaneously converts to the vitamin ("vitamin C").” https://lnkd.in/dq8-3FQ View in LinkedIn

GENE LOSS AND RE-ACQUISITION. “The remains of this non-functional gene with many mutations is, however, still present in the genomes of guinea pigs and humans. It is unknown if remains of the gene exist in the bats who lack GULO activity. The function of GULO appears to have been lost several times, and possibly re-acquired, in several lines of passerine birds, where ability to make vitamin C varies from species to species.” https://lnkd.in/dq8-3FQ View in LinkedIn

SCURVY. “Although scurvy has been known since ancient times, it became a notable cause of large scale deaths in the last 500 years. Scurvy afflicted large land armies and cities in Northern Europe, especially in winter and during siege warfare. In the age of exploration, scurvy became the principle factor limiting sea voyage, often killing many sailors after 2 to 3 months at sea.” https://lnkd.in/dhzW8hm View in LinkedIn

SINGULAR EFFECT. “In all cases so far studied, the inability to synthesize vitamin C is due to mutations in the L-gulono-γ-lactone oxidase (GLO) gene which codes for the enzyme responsible for catalyzing the last step of vitamin C biosynthesis. The bias for mutations in this particular gene is likely due to the fact that losing it only affects vitamin C production.” https://lnkd.in/d66RD9Z View in LinkedIn

PHYLOGENETIC LOSS. “Phylogenetic distribution of the ability to synthesize vitamin C in mammals; other than humans; guinea pigs, bats and dry-nosed primates have lost their ability to produce vitamin C in the same way.” https://lnkd.in/dReYf85 View in LinkedIn