It is not about race. The crime is a result of drug trafficking. Memphis and Nashville are major hubs in the international drug trade.
Memphis...
Population by Race:
White - 34%
African American - 61%
Native American - 0%
Asian - 1%
Hawaiian - 0%
Other/Mixed - 4%
Year|Murder, Man-Slaughter|Forcible Rape|Robbery|Aggravated Assault
2001 158 480 4,338 5,886
2002 151 517 4,240 5,538
2003 126 438 4,297 5,436
2004 105 444 3,771 5,813
2005 137 400 4,464 7,628
2006 147 425 5,311 7,661
2007 128 452 4,870 7,605
2008 138 366 4,787 7,646
Property Crimes:
Rate Per 100K People
2001 8,327
2002 8,363
2003 8,484
2004 8,301
2005 8,362
2006 8,358
2007 8,062
2008 8,011
Year|Burglary|Larceny, Theft|Motor Vehicle Theft
2001 15,874 29,207 9,536
2002 16,340 29,841 9,219
2003 16,900 30,049 8,526
2004 14,621 32,205 7,339
2005 15,844 32,632 8,304
2006 16,450 33,736 6,719
2006 14,613 33,146 6,200
2006 15,874 32,548 5,417
http://www.idcide.com/citydata/tn/memphis.htm
I guess you could say it's more of a "cultural thang". I doubt genetics have much to do with it. Good point.