Yes, that may be true, but according to this source, their DNA is pretty much the same as it was then.
http://www.aish.com/societywork/sciencenature/Jewish_Genes.asp
I'm not sure how that affects appearance, but I would think it does play a part. The main point is that the actress is hardly unbelievable as a first century Jew, IMHO.
I believe the actress is of white Australian (and probably of British or Irish ancestry) and Maori descent. Her coloration might be similar to that of many Middle Easterners, but her features, which are a mix of Polynesian and northwest European, would be different from those of a typical Middle Easterner. (There is also the issue of the actress portraying Mary like a modern day spoiled teenager which is disconcerting and totally contrary to anything in the Bible or oral tradition. But I digress.)
Jews are, of course, the lineal descendants of Abraham and Sarah. However, despite the evident genetic linkage with the ancient Middle East, many Jews, including most in the United States, are European in appearance. Many of Israel's leaders have looked as if they would be more at home in Warsaw or Moscow than the Israel of Bible times.