PEOPLE WHO SPEAK NON-TONAL LANGUAGES ARE MORE LIKELY TO HAVE A MORE RECENTLY EVOLVE FORM OF THE GENES ASPM AND MICROCEPHALIN.
WTF? Tonal languages are found in many different language families and have no "genetic" relationship (in the literal and linguistic sense) per se. Where did this notion come from?
The tower of Babel story is a conflation of a legend from the Enuma Elish (about the building of E-sagila) and a legend about a confusion of languages cognate to the Tale of Enmerkar. Even the biblical story itself is a composite: a story about the building of a city (in order to keep everyone together) and a story about the building of a tower (in order to reach the heavens).
Tonogenesis, btw, usually occurs when segmental contrasts are lost through syllabic changes (e.g. the loss of coda consonants) or phonemic mergers; tones can bifurcate as well, or become adopted via bilingualism.
http://en.wikipedia.org/wiki/Tone_(linguistics)