Genetics of the vegetarian diet FADSJelena Borovac
As humans continue to evolve on Earth, so will our impact on the Earth’s resources. One example of such evolution was recently highlighted in a study which reports a novel genetic component associated with vegetarian diet choices. Basically, the genetics of a specific food processing pathway in vegetarians seems to have evolved to accommodate for their lack of meat consumption.
More specifically, long chain polyunsaturated fatty acids (LCPUFAs), essential bioactive components of our bodies, can either be (1) obtained from animal meat or (2) biosynthesized using an enzyme coded by the FADS2 gene. Animals like cats which are carnivorous have essentially lost their ability to biosynthesize LCPUFAs; but as omnivores, our LCPUFA biosynthesis pathways are still intact. In fact, the genomic determinants of the function of this pathway are subject to selective pressure. Kothapalli and colleagues compared FADS2 genetics between the primarily vegetarian population from Pune, India, and a population selected broadly across the USA.
Strikingly, the genetic profile of the vegetarian population showed a significantly higher occurrence of the FADS2 insertion allele (FADS2 I/I), which serves to enhance LCPUFA biosynthesis. These results strongly suggest that vegetarians have evolved to compensate for the lack of LCPUFA intake from meat through enhancement of LCPUFA biosynthesis. Furthermore, using data from the 1000 Genomes Project, the authors also presented strong evidence of positive selection of the more efficient FADS2 insertion allele in Africa, South Asia, and some East Asia, which correlates with decreased meat consumption in these areas.
Evolutionary exploration of our genetics is like reading about the past and future of our species, our interactions with our surroundings, and the potential we have to positively impact those interactions. Since it is so easy for humans to forget that we are subject to the same selective pressures as all other biological entities around us, it is comforting to know that our conscious choices can lead not only to short-te rm environmental benefits, but also long-term benefits in the form of our own evolution.
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He, Z., et al. (2018). FADS1-FADS2 genetic polymorphisms are associated with fatty acid metabolism through changes in DNA methylation and gene expression. Clin Epigenetics. 2018 Aug 29;10(1):113. doi: 10.1186/s13148-018-0545-5.
Kothapalli, K.S., et al. (2016). Positive Selection on a Regulatory Insertion-Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid. Mol Biol Evol. 2016 Jul;33(7):1726-39.