Answer:
p53 helps the cells from passing on mutations that lead to DNA damage. Hence, it is known as the guardian angel of the cell as it helps fight against cancer. However, if p53 becomes defective or missing, then the mutations will lead to cancer.
Mutations in the p53 can also cause the tumor-suppressing genes to convert into tumor causing genes. Hence, mutations in such kind of genes can be very harmful for the body.
A - the spindle from the kinetochores that attaches to the chrs and pulls them towards the poles is a microfilament.
Ans.
Sickle-cell disorder shows defected red blood cells, due to mutation in gene that code for hemoglobin. The mutated genes for sickle-cell disease are found in higher percentage of sub-Saharan African population as it provides protection against malaria as compared to population of United States.
Malaria is common in sub-Saharan Africa region and there, natural selection favored gene for sickle cells, because it might be beneficial to people having sickle cell disease that makes them able to survive in such condition and transmit their genes to offspring.
On the other hand, in those Africans, who moved to United States, where malaria is uncommon or absent, natural selection favored normal, wild type genes, resulting in fewer people with defected sickle cell.
Thus, the evolutionary process behind this is 'natural selection.'
