32–36. In the Near East,
sheep are generally white and goats are dark brown or black. A minority of
sheep may have dark patches, and goats white markings. It is these uncommon
types to be born in the future that Jacob demands as wages for his unpaid
services. Laban readily agrees, believing that he is getting a bargain on
account of their rarity. He promptly withdraws all the livestock that already
possess the specified characteristics and moves them a considerable distance
away to avoid contact with the rest of the flocks that remain in Jacob’s care.
However, Jacob succeeds in outwitting Laban in the course of the next six years
(31:41). How does he do it?
One account has it that he first
segregates the feebler animals. Then he subjects the sturdier ones to visual
impressions at mating time, in this way influencing the character of the
progeny. Of course, this interpretation rests on folkloristic beliefs and
fallaciously assumes the inheritability of acquired characteristics.
Another explanation is given in
31:8–12. Here the preferred characteristics are obtained through controlled
propagation and transmitted from parent to progeny. Scientifically, the
required results could be achieved by the successive interbreeding of the monochrome
heterozygotes, or the singlecolored animals that carried recessive genes for
spottedness. Such animals are detectable by the characteristic known as
heterosis, or hybrid vigor.
It should be noted that Jacob
claims to have received the idea in a dream. The entire action is thus
attributed to divine intervention, not to Jacob’s ingenuity. This process made
it necessary for Jacob to find a way to advance the mating season so that the
rare types would be induced to engage in reproductive activity before they were
segregated, which they were when the normal mating time approached. If this is
the true explanation, then the varied accounts need not be contradictory. The
first would describe the elaborate display put on by Jacob in order to mask his
secret technique. It is also possible that the three plants placed in the
watering troughs, each known to contain toxic substances and used in the
ancient world for medicinal purposes, could have had the effect of hastening
the onset of the estrous cycle in the animals and so heightened their readiness
to copulate. (Nahum M. Sarna, Genesis
[The JPS Torah Commentary; Philadelphia: Jewish Publication Society, 1989], 212)
