Why was J1 so successful?

[spongetaro]

How can we explain J1 dominance in the middle east, especially in the Arabian Peninsula?
From what I read, it originated in northern Mesopotamia and spread southward before Neolithic.
There seems to have a big founder effect in the Arabian Peninsula similar to R1b in the British islands.
For R1b's dominance we can associate it with the spread of new technologies (horses, bronze weapon...) brought by the Indo European, but what about J1?
What could have brought proto semitic people to be so domiant in south-west Asia?

http://pixelcraftco.com/images/j1-migration.jpg
the map is from Victar of DNA forum.

[Nova123]

http://forwhattheywereweare.blogspot.com/2011/10/genetics-of-marsh-arabs-iraq.html

[Nova123]

http://www.blogger.com/comment.g?blogID=3023805782808412230&postID=283221599911709487&isPopup=true

[Nova123]

http://4.bp.blogspot.com/-CmGLUgzEj5s/ToyGYO2yoMI/AAAAAAAAAow/CoVelJxP4f4/s1600/J1freqvar.png

the map of Y-dna J1

[Goga]

Which haplogroups were in Arabia before J1 arrived? Which haplogroups did J1 replaced?

If I have to guess, I would guess for hg. E, T and L or something.

[khufu]

Yes was my haplogroup and t with mtdna R0a came

From Indian to Yemen you can see it in tinzania now not yemen

[Ozzie]

I do not consider J1 as successful. Outside certain parts of Asia and spots in Africa, it is rare everywhere. Now success is R1b, it is in Europe, the New World countries, Australia, New Zealand, South Africa, it has a greater distribution than J1 despite the Islamic push following the death of the Prophet.

I also agree that J1 is prominent in the Arabian Peninsula due to founder effects. Look at the peninsula, it is mostly desert, hot and inhospitable, it naturally will concentrate humans in places where they can survive, and become inbred.