Section 23.3-- Human Genetics Flashcards
the extent which a certain allele exists in a population
allele frequency
having more fingers or toes than usual
polydactyly
one of the most common hereditary diseases among children in the United States, affecting about 30,000 Americans, mostly of European ancestry
cystic fibrosis
receiving a CF allele from only one parent makes the child a
carrier
occurs when both alleles for a trait are equally expressed in the phenotype of a heterozygous individual
codominance
when the heterozygous phenotype is a blend of the homozygous phenotypes but is distinct from either
incomplete dominance
example of codominance in humans
production of hemoglobin in red blood cells
a person who is SS has ________________________ and makes only abnormal hemoglobin molecules that clump together
sickle cell anemia
if a normal person marries a person with sickle cell anemia, their children must be heterozygous; because these alleles are codominant, both express themselves; some of the hemoglobin molecules are normal and some are abnormal; this is called
sickles cell trait
occurs when there are more than two different alleles of a gene for a particular trait
multiple allele inheritance
one important example of multiple allele inheritance is the
ABO blood group
carbohydrate chains that serve as identification tags
contained in red blood cells that are attached to their cell membrane proteins
antigens
most genes influence not just one trait but several seemingly unrelated traits; this is known as
pleiotropy
involves traits controlled by many different genes
polygenic inheritance
a well-known sex-linked characteristic
a blood-clotting disorder caused by recessive abnormal alleles for the clotting mechanism
hemophilia
