Sickle cell anemia is caused by a point mutation in the gene coding for hemoglobin. this point mutation causes an abnormal form of the protein hemoglobin. individuals who are heterozygous for normal hemoglobin and the mutation experience varying degrees of sickle cell anemia. however, they have increased resistance to the disease individuals homozygous for either normal or sickle cell mutation have increased morbidity and mortality where this disease is endemic. this is an example of

Spherocytosis is an inherited blood disease in which the erythrocytes (red blood cells) are spherical instead of biconcave. this condition is inherited in a dominant fashion, with sph- dominant to sph+. in people with spherocytosis, the spleen "reads" the spherical red blood cells as defective, and it removes them from the bloodstream, leading to anemia. the spleen in different people removes the spherical erythrocytes with different efficiencies. some people with spherical erythrocytes suffer severe anemia and some mild anemia, yet others have spleens that function so poorly there are no symptoms of anemia at all. when 2400 people with the genotype sph- sph+ were examined, it was found that 2250 had anemia of varying severity, but 150 had no symptoms. does this description of people with spherocytosis represent incomplete penetrance, variable expressivity, or both? explain your answer. (3 points)

Marcus's genotype for eye color is bb. olivia has brown eyes, but she is heterozygous for the trait. what percentage of the children have blue eyes? if violet has green eyes and jonas has brown eyes, what is claudia's genotype? how many people in the family have blue eyes?

Building muscle has which of the following effects? it increases the metabolic rate. it relieves pressure on the joints. it slows weight loss considerably.