Obesity and Mitochondria – Research during 2020 in a glance
Published on 01/02/2021
Do you inherit your obesity from your mom?
Maternally inherited mitochondrial DNA (mtDNA) is used to trace the kinship through the female line, it accumulates mutations over several generations. Combinations of these mutations are often specific to geographical regions as well as populations. These groups are called haplogroups. Haplogroups are being increasingly correlated with a broad spectrum of diseases, such as Parkinson’s disease, diabetes, and obesity. Individuals carrying T haplogroup in Austria and Italy are at higher risk of being obese, while haplogroup X was associated with lower obesity risk in Northern Europeans. These findings encouraged the research personnel from Department of Genetics and Bioinformatics to conduct similar studies in Qatari and Kuwaiti populations using mtDNA extracted from exome sequencing data. The studies found that (i) haplogroup X is associated with lower obesity risk (similar to Northern Europeans), while haplogroup J (which is closely related to haplogroup T) is associated with higher obesity risk in Qatari population; and (ii) haplogroup R is associated with lower risk for obesity, while L haplogroup is linked with higher risk of obesity in Kuwaiti population. Furthermore, the studies identified significant associations involving mtDNA variants. “The mitochondrial variants found in the ‘at risk’ haplogroups are predominantly involved in cell energy production”, says Dr. Mohammad Dashti, Scientist.
“By sequencing the D-loop, a smaller region of the mtDNA, the team previously identified haplogroup H related to lower risk of obesity in Kuwaiti Arabs”, says Dr. Eaaswarkhanth Muthukrishna, Scientist. “Interestingly, the new studies revealed haplogroup L, which is common among African populations, associated with higher obesity risk”.
“Tracking haplogroups and/or related genetic variations can help us pinpoint individuals in a given population who are more likely at risk of metabolic disorders,” says Dr. Alphonse Thangavel.
Prof. Fahd Al-Mulla notes that until now, scientists have largely ignored the role of mitochondrial haplogroups or mtDNA variations in understanding obesity and energy imbalance and our studies serve as an eye-opener. Al-Mulla and Muthukrishna have begun a large-scale mitochondrial genome project to refine the influence of mtDNA on obesity, diabetes, and related metabolic complications in theKuwaiti population.
https://www.natureasia.com/en/nmiddleeast/article/10.1038/nmiddleeast.2021.20
Dashti, M., et al. Mitochondrial haplotype J associated with higher risk of obesity in the Qatari population. Scientific Reports 11:1091 (2021) http://dx.doi.org/10.1038/s41598-020-80040-7
Dashti, M., et al. Delineation of mitochondrial DNA variants from exome sequencing data and association of haplogroups with obesity in Kuwait. Front. Genet. (2021) https://doi.org/10.3389/fgene.2021.626260
Eaaswarkhanth, M., et al. Mitochondrial DNA D-loop sequencing reveals obesity variants in an Arab population. Appl. Clin. Genet. 12:63-70 (2019). https://doi.org/10.2147/TACG.S198593
