17.5 codominance & multiple alleles Flashcards
what is codominance?
both alleles are expressed in phenotype
what is an example of multiple alleles?
blood group A, B, O
which blood antigen groups are codominant?
A & B
which blood antigen group is recessive?
O
why would a individual only have 2 alleles from a multiple-allele gene?
we only have 2 homologous chromosomes therefore only 2 alleles at the same time
how many pairs of human chromosomes are autosomes and what are those?
22, homologous & identical in appearance
which sex chromosome is shorter and shaped differently?
Y
what is the name for a gene carried on a sex chromosome?
sex-linked
where will recessive genes of the X chromosome appear more often in males?
non-homologous portion
what is haemophilia?
slow blood clots, slow / persistent internal bleeding (especially in joints)
what is haemophilia caused by?
recessive allele which codes for a non-functional protein required in the clotting process
