Southern Arabia is the home of the Joktanites who Josephus called "Horites".
Alice C. Linsley
To Eber were born two sons: the first was called Peleg, because it was in his time that the earth [eretz] was divided, and his brother was called Joktan. (Genesis 10:25)
This diagram shows the division. The Hebrew word eretz and should be rendered "territory" instead of earth. It appears that Eber broke his territory into two, assigning separate territories to each royal son. The word eretz has multiple meanings: earth, land, soil, and territory. Since this passage deals with royal sons, the most appropriate word choice for the context is territory. Eber split his kingdom into two. Peleg ruled over one territory and Joktan over the other.
Josephus noted a connection between Abraham's cousin wife Keturah and the Joktanites. Keturah resided at the Well of Sheba (Beer-Sheba) as she was of the royal house of Sheba. So it is apparent that the lines of Peleg and Joktan intermarried, as did the royal lines of Cain and Seth, Ham and Shem, and Abraham and Terah.
That Eber divided the territory suggests various possibilities. 1) His holdings were too vast to be ruled from one location. 2) Peleg and Joktan may have been twins, born to the principal wife, Eber's queen. Peleg comes to represent the populations known as Arameans, and Joktan represents the Afro-Arabians. Though separate, the two populations share a genetic history and common religious beliefs and practices.
"the children inside her struggled with each other, and she said, “Why is this happening to me?” So Rebekah went to inquire of the LORD, and He declared to her: “Two nations are in your womb, and two peoples from within you will be separated; one people will be stronger than the other, and the older will serve the younger."
In the case of Rebekah's twin boys we are told which is the older: Esau. Esau was Isaac's proper heir and Jacob attempted to steal the royal birthright. However, Jacob became the sent-away son and Esau remained in Edom. Esau never served Jacob, except to greet Jacob upon his return to Edom in a spirit of forgiveness.
The Bible provides very little information about Peleg who is claimed to be Eber's first born. The Bible and extra-biblical sources offer much more information about Joktan. These Horite Hebrew rulers came to rule over separate territories, represented by the Arameans and the Arabians. The Aramean territory was called "Eber-Nahar" and was comprised of Syria, Phoenicia, and Cyprus. The Joktanite clans resided in Southern Arabia. Another way to look at this division is to speak of "Afro-Asians" and "Afro-Arabians" since all have ancestral and linguistic roots in Africa.
Joktan is a royal name. The name has several variants, including Yaqtan, Jochin, and Jokshan. In Genesis 25 we read that Keturah bore Abraham Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. Jokshan was the father of Sheba and Dedan. The earliest Arabic texts are called "Dedanite." King Solomon named one of the twin entrance pillars of the temple Jochin after his maternal great great grandfather. The other pillar was named Boaz, after Solomon's paternal great great grandfather.
Today the population of Southern Arabia is Muslim, with the exception of Yemenite Jews. Genetic studies indicate that the inhabitants are mainly in Y-DNA groups J1 and T1. These have a wide dispersion: Anatolia, Yemen, Egypt, Saudi Arabia, Madagascar, the Fertile Crescent, the Caucasus, and even among a small number of Mongolians. Where J1 and T1 are found in high frequency, mtDNA haplogroups HV, N1, and U3 are also present. ZS226 is a subclade of J1. ZS227 includes the Kohanim (priest) haplotype found among both Jews and Arabs.