It is easy to think that the Abbasid caliphate was an “Arab” empire. The emperors themselves were proud to trace their lineage back to Abbas, uncle of Prophet Muhammad. Yet within 150 years of its founding, Arab genes made up 2% of the genetic makeup of the emperors, and this remained so until the very end.

The first significant emperor with Indo-European genes was the half-Persian al-Ma’mun, who had his capital at the Persian city of Merv in Central Asia for ten years before moving to Baghdad. During his reign a trend started for preferring Greek and Persian concubines for producing the next generation of emperors, so that the amount of Arab genes declined to insignificant amounts. Al-Muqtadir, who reigned from 908 – 929 CE was nearly 98% Indo-European.

It can be seen from the table below that the Abbasid caliphate was an Arab empire at its beginning, transformed into an Indo-European empire (with four successive emperors having 97%+ Indo-European genes!) during its Golden Age, then started to increasingly mix with Turkic genes during its decline.

Reign	Name	Father	Mother	Race	Indo-European Percentage*
750 – 754	Al-Saffah	Muhammad (Arab)	Raita (Arab)	100% Arab	0%
754 – 775	Al-Mansur	Muhammad b. Ali (Arab)	Sallamah (Berber slave)	50% Arab, 50% Berber	0%
775 – 785	Al-Mahdi	Al-Mansur	Arwi (Yemeni Arab)	75% Arab, 25% Berber	0%
786 – 809	Harun al-Rashid	Al-Mahdi	Al-Khayzuran (Arab slave)	87.5% Arab, 12.5 Berber	0%
813 – 833	Al-Ma’mun	Harun al-Rashid	Marajil (Persian slave)	50% Persian, 43.75% Arab, 6.25% Berber	50%
833 – 842	Al-Mu’tasim	Harun al-Rashid	Marida (Turkic slave)	50% Turkic, 25% Persian,  21.875% Arab, 3.125 Berber	25%
842 – 847	Al-Wathiq	Al-Mu’tasim	Qaratis (Byzantine Greek slave)	50% Greek, 12.5% Persian, 10.9375% Arab, 1.5625% Berber	62.5%
847 – 861	Al-Mutawakkil	Al-Mu’tasim	Shuja (Persian slave)	56.25% Persian, 25% Greek, 5.46875% Arab, 0.78125% Berber	81.25%
870 – 892	Al-Mu’tamid	Al-Mutawakkil	Fityan (Persian slave)	78.125% Persian, 12.5 Greek, 2.734375% Arab, 0.390625% Berber	90.625%
892 – 902	Al-Mu’tadid	al-Muwaffaq, son of Al-Mutawakkil and Umm Ishaq, a Greek slave. Race: 56.25% Greek, 39.0625% Persian, 1.3671875% Arab, 0.1953125% Berber)	Dirar (Greek slave)	78.125 Greek, 19.53125% Persian, 0.68359375% Arab, 0.09765625% Berber	97.655%
902-908	Al-Muktafi	Al-Mu’tadid	Jijak (Greek slave)	89% Greek, 9.7% Persian, 0.34% Arab, 0.04% Berber	98%
908 – 929	Al-Muqtadir	Al-Mu’tadid	Shaghab (Greek slave)	94.5% Greek, 4.88% Persian, 0.17% Arab, 0.02% Berber	98%
946 – 974	Al-Muti	Al-Muqtadir	Slavic slave	50% Slavic, 47.26% Greek, 2.44% Persian, 0.08% Arab, 0.01% Berber	98%
974 – 991	Al-Ta’i	Al-Muti’	Unknown	50% Unknown, 25% Slavic, 23.6% Greek, 1.22% Persian	49.82%
991 – 1031	Al-Qadir	Al-Muttaqi, son of al-Muqtadir. Race: 50% Unknown, 47.2% Greek, 2.44% Persian, 0.08% Arab	Slave of uknown origin	75% Unknown, 23.6% Greek, 1.2% Persian (Al-Qadir is described as being “white” in history books, therefore it is likely that his mother was Greek or Persian)	24.8%
1031 – 1075	Al-Qa’im	Al-Qadir	Badr al-Daji (Armenian slave)	50% Armenian, 37.5% Unknown, 11.8% Greek, 0.6% Persian	62.4%
1075 – 1094	Al-Muqtadi	Al-Qa’im	Urjuman (Armenian slave)	75% Armenian, 18.75% Unknown, 5.9% Greek	80.9%
1094 – 1118	Al-Mustazhir	Al-Muqtadi	Altun Khatun (Turkic woman, prob. Seljuk princess)	50% Turkic, 37.5 Armenian, 9% Unknown, 2.95% Greek	40.45%
1118 – 1135	Al-Mustarshid	Al-Mustazhir	Kumush Khatun (Turkic woman, probably Seljuk princess)	75% Turkic, 18.75% Armenian, 4.8% Unknown, 1.47% Greek	20.22%
1136 – 1159	Al-Muqtafi	Al-Mustazhir	Fatima Khatun (Turkic woman, probably Seljuk princess)	87.5% Turkic, 9.375% Armenian, 2.34% Unknown, 0.73% Greek	10.1%
1160 – 1170	Al-Mustanjid	Al-Muqtafi	Tawus (“Thawus”) al-Karaji, slave (Most likely Persian, al-Karaji refers to the city of Karaj in Iran in Medieval last names)	50.019% Persian, 43.75% Turkic, 4.68% Armenian, 1.1% Unknown, 0.3% Greek	55%
1170 – 1180	Al-Mustadi	Al-Mustanjid	Ghaddah (Armenian slave)	52.3% Armenian, 25% Persian, 21.8% Turkic	77.3%
1180 – 1225	Al-Nasir	Al-Mustadi	Zumurrud (Turkic slave)	60.9% Turkic, 26.1% Armenian, 12.5% Persian	38.6%
1226 – 1242	Al-Mustansir	Az-Zahir, son of al-Nasir and unknown mother. Race: 50.14% Unknown, 30.4% Turkic, 13.08% Armenian, 6.25% Persian)	Turk Khatun (Turkic slave)	65.2% Turkic, 25% Unknown, 6.5% Armenian, 3.1% Persian	9.6%
1242 – 1258	Al-Mustasim	Al-Mustansir	Concubine of unknown origin	62.5% Unknown, 32.6% Turkic, 3.2% Armenian, 1.5% Persian	4.7%

Sources: Wikipedia, The Slave Girls of Baghdad by F. Matthew Caswell, Islam in History by Bernard Lewis, Islamic Culture, Volume 2 (1928), various Arabic-language sources.

The table omits emperors who ruled for very short periods of time and/or who did not contribute to the genes of succeeding emperors.

* The values in this column are capped to 98%: Due to the fact that the Y-chromosome can only be inherited from one’s male relatives, and due to the fact that it makes up 2% of the genome, the Y-chromosome of the emperors would have been necessarily Arab, and therefore their percentage “Arab-ness” couldn’t have fallen below 2%, so that the most Indo-European that an Abbasid emperor could be would have been 98% realistically.