Do genes make you responsible for murder, second-degree murder or manslaughter?

Anthony Yepez beat to death the stepfather of his girlfriend, burned the body to get rid of evidence and then took the victim’s car and fled.
If you were a juror in this case, would you find Yepez guilty of first-degree murder (“willful, deliberate, premeditated killing”), second-degree murder (“a strong probability that death or bodily harm would result”) or manslaughter (“unintentional killing”)?
Genetic testing revealed that Yepez has a low-activity m