In a species of fish, a black spot on the dorsal fin is observed in males and females. a fish breeder carries out a pair of reciprocal crosses and observes the following results. cross i parents: black-spot male × nonspotted female progeny: 22 black-spot males 24 black-spot females 25 nonspotted males 21 nonspotted females cross ii parents: nonspotted male × black-spot female progeny: 45 black-spot males 53 nonspotted females