Genesis on genetics

This is another archival report, originally written for the old blog in 2008.

Here’s an interesting one: Genesis chapter 30. If you think Darwin got inheritance wrong, try the Bible.

30:28 And he [Laban] said, Appoint me thy wages, and I will give it.

30:29 And he said unto him, Thou knowest how I have served thee, and how thy cattle was with me.

30:30 For it was little which thou hadst before I came, and it is now increased unto a multitude; and the LORD hath blessed thee since my coming: and now when shall I provide for mine own house also?

30:31 And he said, What shall I give thee? And Jacob said, Thou shalt not give me any thing: if thou wilt do this thing for me, I will again feed and keep thy flock.

30:32 I will pass through all thy flock to day, removing from thence all the speckled and spotted cattle, and all the brown cattle among the sheep, and the spotted and speckled among the goats: and of such shall be my hire.

30:33 So shall my righteousness answer for me in time to come, when it shall come for my hire before thy face: every one that is not speckled and spotted among the goats, and brown among the sheep, that shall be counted stolen with me.

30:34 And Laban said, Behold, I would it might be according to thy word.

30:35 And he removed that day the he goats that were ringstraked and spotted, and all the she goats that were speckled and spotted, and every one that had some white in it, and all the brown among the sheep, and gave them into the hand of his sons.

30:36 And he set three days’ journey betwixt himself and Jacob: and Jacob fed the rest of Laban’s flocks.

30:37 And Jacob took him rods of green poplar, and of the hazel and chesnut tree; and pilled white strakes in them, and made the white appear which was in the rods.

30:38 And he set the rods which he had pilled before the flocks in the gutters in the watering troughs when the flocks came to drink, that they should conceive when they came to drink.

30:39 And the flocks conceived before the rods, and brought forth cattle ringstraked, speckled, and spotted.

30:40 And Jacob did separate the lambs, and set the faces of the flocks toward the ringstraked, and all the brown in the flock of Laban; and he put his own flocks by themselves, and put them not unto Laban’s cattle.

30:41 And it came to pass, whensoever the stronger cattle did conceive, that Jacob laid the rods before the eyes of the cattle in the gutters, that they might conceive among the rods.

30:42 But when the cattle were feeble, he put them not in: so the feebler were Laban’s, and the stronger Jacob’s.

30:43 And the man increased exceedingly, and had much cattle, and maidservants, and menservants, and camels, and asses.

So, I think the deal here is that Jacob makes some pact where he gets to take all of the stripey, speckled, and spotted cows, sheep, and goats, from this other dude Laban’s stock. He does this, leaving Laban with homogeneous flocks of plain individuals. He then attempts fraud by making Laban’s plain individuals mate while looking at stripey things, so that the offspring will be stripey, and Jacob can claim they are his own. And, hey, guys, it totally worked.

It’s not actually at all surprising that the offspring of two plain individuals turn out stripey, speckled, or spotty. That sort of thing is pretty normal. Traits can skip generations and reappear later for a variety of reasons. It could be that one or the other trait is linked to a dominant/recessive gene system; or that they are influenced by complicated combinations of genes, which are shuffled in each generation; or that they are capable of being thrown either way by developmental switches. Indeed, it’s possible even to speculate on reasons why the “feebleness” of cattle might be linked to the tendency to breed true for more traits.

So, assuming that the story has some basis in reality (lets pretend, anyway), Jacob probably just developed a superstition. A convenient myth to explain a mysterious natural phenomenon, while allowing him to believe that he had some influence over that phenomenon. Perhaps he noticed some stripey pattern in the landscape one day, noticed that there was mating going on in the vicinity of the stripes, and then noticed the stripey lambs being born. A meaningless correlation would then appear, superficially, to be a principle of inheritance. From there, the superstition would develop as the believer started counting hits, forgetting misses, and discovering his “ability” to select the stronger more desirable individuals as parents (or post-hoc reasoning that because it has sired a stripey calf, it must be a strong bull).

Alternatively, of course, Goddidit.

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