assertFalse(new Sequence("prot", "ACGTACGTACGTNNNNNNNN").isProtein());
// test RNA with X
assertFalse(new Sequence("prot", "ACGUACGUACGUACTGACAXX").isProtein());
assertFalse(new Sequence("prot", "ACGTACGTACGTNNNNNNNN").isProtein());
// test RNA with X
assertFalse(new Sequence("prot", "ACGUACGUACGUACTGACAXX").isProtein());