Patterns of inheritance - exam

what is sex-linked inheritance w fathers and mothers

primarily on the x chromosome because the Y chromosome is very small and contains few genes

fathers pass sex linked alleles to ALL of their daughters but to NONE of their sons

mothers can pass sex-linked alleles to both sons and daughters

inheritance of sex linked traits

if a sex linked trait is caused by a recessive allele, a female will only express that trait if she is homozygous

a male who receives the sex linked recessive allele from the mother will express the trait - cant be carriers, males are not homozygous or heterozygous in this case

trait can skip generations

what is the case for males with sex linked traits

since males only need to receive 1 allele from the mother, they are more likely to be affected by sex linked traits

what is autosomal inheritance - recessive

individual expressing trait has two normal parents

two affected parents cant have an unaffected child

what is autosomal inheritance - dominant

every affected person has at least one affected parent

each generation will have affected individuals

what are genetic diseases - x linked

hemophilia(absence of one or more proteins req. for blood clotting), duchenne muscular dystrophy (progressive weakening of muscles, missing muscle protein due to mutation in a gene on the x chromosome), color blindness

what are genetic diseases - autsomal

achondroplasia, huntington’s disease, cystic fibrosis