Name: 14 Codominance Certain birds can have solid blue, solid white, or white an
ID: 132232 • Letter: N
Question
Name: 14 Codominance Certain birds can have solid blue, solid white, or white and blue-tipped single allele. The blue-tipped feathers are the heterozygous condition. crossed with a bird with solid white feathers 6. feathers. This trait is controlled by a A bird with blue-tipped feathers is What is the predicted phenotypic ratio of the offspring? Show your work. Incomplete Dominance 7. Malaria is a parasitic disease common in tropical areas. When a mosquito carrying the parasite bites a person the parasite enters the bloodstream and invades red blood cells. Sickle cell anemia is a disease that causes red blood cells to sickle or curve/deform. This is bad for carrying oxygen, but good because these deformed cells are immune to malaria. A person with sickle cell anemia (ss) is immune to malaria. If a person is Ss they are resistant to malaria. This condition is also better for carrying oxygen because they make both normal and sickled red blood cells. A person who is SS makes only normal red blood cells and is not resistant to malaria. A man and a woman living in a tropical area where malaria is prevalent and health care is not accessible want to have a child. Both parents have a heterozygous genotype and are resistant to malaria. What is the chance (as a percent) that the child will be resistant to malaria. Show your work.Explanation / Answer
6. Let us first describe the genotype of the genes controlling the feather characteristic in birds.
BB : Blue coloured feathers; ww : White coloured feathers; Bw: white and blue tipped feathers
Bw : heterozygous in nature which displays codominance and both the alleles are being expressed.
According to the question, cross between bird with solid white feathers (ww) with another having blue-tipped feathers (Bw)
Since there are equal number of phenotypes, blue-tipped feathers and solid white feathers in the offsprings after crossing, the phenotypic ratio is 1:1.
7. Sickle cell anemia follows autosomal recessive pattern of inheritance. According to the question,
S : allele representing normal hemoglobin; s : allele representing abnormal hemogobin
Ss : genotype representing heterozygous condition and imparts resistance to malaria
ss : sickle cell anemia
SS : normal hemoglobin and sensitive to malaria
As described in the problem, both the parents possess heterozygous genotype and are resistant to malaria, i.e. the genotypes are Ss (man; paternal) and Ss (woman; maternal).
After crossing,
Thus, out of the four progeny population, two display heterozygous (Ss) genotype,i.e. would be resistant to malaria.
Thus, there exists 50% chance (2/4*100) of the child to be resistant to malaria by possessing heterozygous genotype.
B w w Bw (blue-tipped feathers) ww (solid white feathers) w Bw(blue-tipped feathers) ww (solid white feathers)Related Questions
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