試題詳解

57. An unusual example of natural variation in the ploidy occurs in some species. Which of the following statements describes the endopolyploidy most correct?
(A) The endopolyploidy is due to a cell division defect, and it occurs only in lower animals.
(B) Endopolyploidy is the occurrence in somatic tissues； the most common is in human nerve and epidermal cells.
(C) An example of endopolyploidy is in the salivary gland cells of Drosophila, the pairs of chromosomes double approximately 9 times.
(D) The chromosomes undergo repeated rounds of chromosome replication without cellular division, the backup copies of chromosomes kept in vacuoles that segregated away from the functional copies.
(E) The entire organism has extra copies of certain chromosomes, for producing additional gene products.