Multifactorial causes leading to disease?
SPina bifida
Cleft lip/palate
diabetes
Schizophrenia
hemizygous
Hemizygous only one allele refers to a locus on an X chromosome in a male
Genetic imprinting?
For some genes only 1 out of the 2 alleles is active, the other is inactive
For particular genes it is always the paternal or the maternal allele