E-M81 a subclade of E-M35
1) E-M81 does not date back to the Paleolithic period. TMRCA dates this lineage to 5.6 kya as per Cruciani et al. 2004. Semino et al 2004 dates it to 8.6 +/-2.4kya.
2)
E-M81 shows up in high frequency in
Berber North Africans but not
North African Arabs. For example, Moroccan Arabs have E-M81 at ~23% ,Algerian Arabs ~45% , and Arab Tunisians at ~27.6%(Reguig et al 2014).
3)E-M81 is found in the Middle East among Lebanese 1.2–2.4%, Turkish 2.5–8.7%, Bedouins ~3.6%, and Sephardic Jews ~5%.
4) In European populations E-M81 is visible in Spain 1.6–5.3%, with the exception of Pasiegos 18% and Cantabrian non-Lebaniego 17% as per Maca-Meyer et al. 2003. The contribution in Southern Europe is thought to be at a recent arrival via Moorish period of Islamic Expansion. E-M81 is visible in Portugal, Madeira and Acores at a rate of 5-8%.
Di Gaetano et al. 2009 estimated a contribution of 6% in the Sicilian gene pool
5) E-M81 ancestor is E-M35 (whose ancestor is E-M215 24kya) is dated to ~22-18 kya. It's sister clade E-M78 is posited to originate in Egypt and is dated to ~17kya.
http://mbe.oxfordjournals.org/content/24/6/1300.full
A northeastern African origin for haplogroup E-M78 implies that E-M215 chromosomes were introduced in northeastern Africa from eastern Africa in the Upper Paleolithic, between 23.9 ky ago (the upper bound for E-M215 TMRCA in eastern Africa) and 17.3 ky ago (the lower bound for E-M78 TMRCA here estimated, fig. 1).
6) Although it is rare in the East Africa it shows up in Sudanese at ~5%,Egyptians at ~9.5% and Somalis at ~1.5% as per
Ahmed Reguig et al. 2014 .
7) In West African Sahelian countries it shows up at a frequency of Maurentania 55.6%,Mali 29.5% and Niger 9% as per
Ahmed Reguig et al. 2014 .
8) E-M81 has 2 rare descendant subclades E-M107 (which I believe is found in Mali) and E-M165. Both of these subclades are extremely rare.Its other subclade M183 shows up in Moroccans at ~65 - 83%.
9) E-M81 peaks in Southern Moroccan Berbers at a rate of ~98.1%,Central Moroccan Berbers ~89.8%,North Moroccan Berbers ~79.1%, and Mozabite Algerians ~80%.In conclusion North African Arabs show a decreased frequency of E-M81.