Question

Drosophila melanogaster, the fruit fly, has a 2n chromosome number of 8 (4 chromosomes – 3 autosomes and 1 sex chromosome). Assume that you are microscopically examining the mitotic and meiotic cells of this organism. You note that in the female, two chromosomal pairs are metacentric and two pairs are acrocentric.
Draw the chromosomal configurations as you would expect to see them at the stages listed:
i. mitotic metaphase
ii. primary oocyte (meiotic metaphase I)
iii. secondary oocyte (meiotic metaphase II)
iv. oocyte (gamete G1)
v. second polar body
Given that the previously mentioned cells are from an individual heterozygous for two independently segregating, autosomal loci, plum eyes and curled wings, place appropriate symbols (of your designation) on separate chromosomes in the drawings you made for part (a). Assume no crossing over. There may be more than one correct answer. Indicate which allele is the dominant and which is the recessive. (Capital letters are usually used for dominant and lowercase for recessive.)

Answer 1

Mitotic metaphase:

Primary oocyte (meiotic metaphase I):

Secondary oocyte (meiotic metaphase II):

Oocyte (gamete G1):

Second polar body: