
Background
Why should we investigate Central Asian and Transcaucasian countries in disease-diversity research?

Diversity in human genetics and genomics research is crucial
The modern human genetic diversity, resulting from demographic history and adaptive environment-driven selection in different populations, considerably influences the genetic and phenotypic diversity of human diseases. The frequency of many rare genetic variants and haplotypes is differently distributed across various populations and their association with diseases could grossly be determined by the ethnic origin 1, 2, 3. This is applicable for both diseases with Mendelian and complex inheritance.
The study of genetic associations with diseases has largely been focused on European populations, which has significant implications for predicting disease risk across global populations 4, 5, 6, 7. This Eurocentric bias and under-representation of ethnically diverse populations hinder our ability to fully comprehend the genetic basis of human diseases, could result in inaccurate risk assessments and a lack of interventions in under-represented populations, and exacerbate health disparities.
Therefore, studying diverse populations is critical to improving the precision of medical care globally and enhancing our understanding of the genetic architecture of diseases.
Currently, many world regions remain underrepresented in modern human genetic research, including genetic association studies. Central Asia and Transcaucasia (CAT) is one such region that is significantly underrepresented.
CAT plays an important role in elucidating global human genetic variation and ensuing disease diversity.
1. The overall population of CAT is 93 million.
2. Located in the middle of Eurasian continent
3. CAT has the highest genetic diversity in Eurasia and the highest genetic diversity in the world after Africa
4. Extremely diverse population (over 125 nationalities)
5. CAT is the place where western Eurasian lineages meet eastern Eurasian genetic strata
6. The presence of western and eastern mtDNA sequences found in CAT (55%-41%)
7. CAT played a key role in the formation of ancient and modern humans
The available studies suggest that CAT populations are genetically unique and diverse due to the considerable admixture of western and eastern Eurasian lineages. Firstly, this highlights the importance of CAT in elucidating global human genetic variation and ensuing disease diversity 8, 9, 10. Secondly, this genetic diversity provides a valuable resource for the study of rare genetic diseases as well as common diseases and can inform the development of new treatments and cures.
References:
1. Balaresque et al, 2007
2. Gurdasani et al, 2019
3. Sirugo et al., 2019
4. Cavalli-Sforza et al., 2005
5. Lu et al., 2014
6. The 1000 Genomes Project Consortium, 2015
7. Gurdasani et al., 2019
8. Comas et al., 1998
9. Martínez-Cruz et al., 2011
10. Røyrvik et al., 2018