Concerning of genetics, we could conclude such things only if we have detailed genetic picture of entire Slavic and entire Indian population. (Which was not done yet as far as I know).
So only cathegory of similarites left to us was cultural. Persian culture (both Islamic and pre-Islamic) is far more closer to us than Indian.
Well the point is both have nothing in common with us today in the way we look.
Ones are mostly Indian while others are mostly Semitic.
Thought as i said at least with Indians we share proto-Indo-European roots as well as some haplogroups indicating of something similar thousands of years ago…Genetics testing have been done in india and mostly the High Castes have R1a blood and are much more Europid then the average indian we have in mind when we image them. But i don't understand the Iran fanboyism, they are neither Europid, neither have IE roots, but just Caucasoid. Thought if one is going to research as far as i have read on numerous forums in India their High Caste has mostly Indians with Europid features and light eyes, while in Iran among Isolated people (usually in mountains and such) one can find as well Europid light eyed examples. Maybe it indicates that both Indo-Europeans and Iranians(Aryans) where more Europid in it's ancient history and turned the way they are today due to influx of other pheotypes.
Out of all Iranian speaking people only by our standards what we would call Europid are Nuristani Indo-Iranians in Afghanistan:
Nuristani are an Indo-Iranian tribe in Afghanistan
they are settled in the mountainous parts of the country and thus were preserved very well.
The Nuristanis are a people whose ancestors practised what was apparently an ancient Indo-Iranian polytheistic Vedic religion until they were conquered and converted to Islam in the late 19th
genetically the are most similar to Kalash people of Pakistan, again an isolated case of old Indo-Iranian people
[img width=700 height=525]http://www.galyat.net/wp-content/uploads/2012/03/Galyat-Landscapes.jpg”/>
and we have high cast Indians which show more europid features than the lower casts in Indian society: