Of the different genes represented by your mutants you are p

Of the different genes represented by your mutants, you are particularly interested in further characterizing one of the genes that you have now named shaven (s). A lab mate who studies body color in files is going on vacation and asks you to watch his true breeding ebony (e) fly line and reminds you that wild type body color is yellow-brown. While your lab mate is on vacation you decide to cross a shaven female to an ebony male. You find that all the F1 flies have bristles and are yellow-brown. Indicate the genotypes for the parents (P) and offspring (F1) P: s/s; e/e (female) x s+/s+; e+/e+ (male) F_1. s+/s; e+/e P: s+/s+; e+/e+ (female) x s/s; e/e (male) F_1: s+/s; e+/e P: s/s; e+/e+ (female) x s+/s+; e/e (male) F_1. s+/s; e+/e P: s+/s+; e/e (female) x s/s; e+/e+ (male) F_1: s+/s; e+/e P: s+/s; e+/e (female) x s+/s; e+/e (male) F_1; s+/s; e+/e

Solution

He cross a Shaven female, which is recessive bristle character of Drosophila (s), with a ebony male which is also recessive body colour of Drosophila sp.

Now genotype of Shaven female may be either s/s, e/e or s/s, e+/e+. Here s/s represents recessive character of bristle means shaven and e/e represents recessive body colour means ebony. Besides this e+/e+ means dominant character of body colour that is yellow-brown. But the body colour in shaven female is not given that mean it should be dominant. So, genotype of shaven female is s/s, e+/e+.

Genotype of Ebony male may be either s/s, e/e or s+/s+, e/e. Here s+/s+ means dominant and normal bristle. As here body colour is ebony so genotype of ebony colour will be recessive (e/e). And as there is no particular information about bristle in male so genotype of bristle will be dominant (s+/s+). so, genotype of ebony male is s+/s+, e/e.

Now if there is a cross between shaven female and ebony male, F1 generation will be:

Shaven Female                                                      Ebony Male

s/s, e+/e+                            X                                  s+/s+, e/e..........................................P

                              s+/s, e+/e                                         ............................................F1

Now, the genotype of F1 gamete s+/s, e+/e is normal bristle yellow-brown body colour. As s+ is dominant over s, so the bristle is normal. Also e+ is dominnt over e means ebony so the body colour is normal ( yellow -brown).

So, the ans is [C].