Question

You think you have discovered a novel toxin-antidote selfish genetic element in strain T elegans in which the toxin is produced by the embryo and the antidote is deposited by the mother. You cross strain T with strain U, which lacks the selfish genetic element to produce an F1 hybrid strain. What percentage of offspring would die from the following genetic crosses? Please answer by indicating"N96," where N is the percentage of offspring who would die. F1 male x F1 hermaphrodite T male x F1 hermaphrodite F1 male x U hermaphrodite

Answer 1

F1 hybrid from cross T and U is = TU ( toxin resistant duse to presence of antidots)

in First case- F1 male is XO

F1 hermaphrodite is XTU & OTU (because hermaphrodite animal has both male and female gametes)

	X	O
XTU	XXTU	XOTU
O	XO	OO

50% progeny will die due to lack of T strain

In case of 2- T male (XT, OT) and F1 hermaphodite

	XT	OT
XT/XT	XXTT	XOTT
XO	XXOT	XOOT

0% progeny die in this case because all progeny has T strain

In case 3- F1 male ( XT, OT ) and U hermaphodite

	XT	OT
XU	XXTU	XOTU
OU	XOTU	OOTU

25% progeny will die because F1 male restore the T starin with antidote.