From MedicalXpress, a website that writes up scientific papers:
Genome study shows that Iran’s population is more heterogeneous than previously believed
September 25, 2019
University of Cologne
The first genome-wide genetic characterization of the Iranian population reveals highly heterogeneous ethnic groups with a high degree of genetic variation. Members of eleven selected Iranian ethnic groups took place in the study, including large groups such as Iranian Persians and Azeri, but also smaller ones like Arabs, Baluchi, Gilaki and Kurds.
… In many cases, their source goes back many thousands of years. The results, obtained from the first genome-wide genetic characterization of the Iranian population by this team, appeared in PLOS Genetics, titled “Distinct genetic variation and heterogeneity of the Iranian population.”
The researchers analyzed the genetic data of 1,021 volunteers whose parents and grandparents identified themselves as belonging to one of 11 selected Iranian ethnic groups, including large groups such as Iranian Persians and Azeri, but also smaller ones like Arabs, Baluchi, Gilaki and Kurds. These volunteers were sampled all over Iran. They found out that Iranian Persians and Kurds, for example, exhibit high in-group genetic variation which is larger than that of, for example, Germans. However, the entire gene pool has remained largely unchanged over at least the past 5,000 years, but probably [not over] the past 10,000 years.
… Furthermore, Britons and North Italians are genetically more similar than some ethnic groups in Iran. “This was somewhat surprising,” Michael Nothnagel said. “Until recently, many scientists had assumed genetic variation across present-day Iranians to be rather homogeneous.”
My impression is that Middle Eastern culture has a strong tendency toward endogamy and passing on peoplehood. The Jews are the most famous Middle Eastern group that is still around, but there are all sorts of others despite the impact of first Christianity and then Islam, both of which have universalizing tendencies, on the Middle East over the last 2000 years.