Jacob’s Strange Breeding Method

This question came up when reading the Jacob/Laban story:

In Genesis 30, why does Jacob put sticks in front of the sheeps and why does that change the color of the breeding?

Short Answer

Jacob made an agreement with Laban to care for the latter’s flocks. The payment to Jacob will be any unusually-coloured sheep and goat from the flock; any white sheep and black goats (the usual colour for sheep and goats) will be Laban’s. Laban thought he was getting a bargain (cheap and good labour from Jacob), but instead, the majority of the offsprings from his flock turned out to be speckled or spotted, making Jacob rich at the expense of Laban.

Jacob used some very unusual methods to make sure the flocks produce offsprings that will go to himself. He made striped sticks and put them in front of the flock, and somehow, the flock produced lots of speckled and spotted offsprings. This isn’t, of course, how breeding or genetics work, so how do we explain Jacob’s success?

Here are the most popular explanations^[1]A few commentaries are listed in the References section below.:

1. Jacob believed in folklore or sympathetic magic (what the mother sheep saw when she got pregnant will cause her lambs to turn out that way). In the Middle Ages, many people in Europe also believed this. This view is popular with people who take a low view of the Bible. They believe that the Bible is full of errors and myths, is unscientific, and has no place in today’s scientific age.
2. Jacob might (or might not) believe in folklore, but it was God who made sure that things turned out in Jacob’s favour. That is, even though the folklore doesn’t make sense, God stepped in to ensure that most of the lambs turned out to be speckled or spotted.
3. There are actually scientific (or genetic) principles involved, some of which we now know, others we still don’t know about, and Jacob used these principles to produce majority speckled and spotted lambs.

I prefer a combination of #2 and #3 explanations. There are some genetic principles that Jacob used, and I think God also helped him by pointing out certain things to him. With his knowledge and experience of caring for sheep and goats, genetic principles, and God’s help, Jacob was able to get rich at the expense of his uncle Laban.

More Detailed Answer

Right after his son Joseph was born (finally, Jacob’s favourite wife Rachel gave birth herself to a son, this son will become Jacob’s favourite son), Jacob decided to leave his uncle Laban and return to Canaan. Laban wanted to keep him on, because Laban is getting cheap labour, and Jacob has made Laban rich (because of God’s blessing, Gen 30:27–30). So they negotiated an agreement:

Genesis 30:31–34 ESV

He said, “What shall I give you?” Jacob said, “You shall not give me anything. If you will do this for me, I will again pasture your flock and keep it: let me pass through all your flock today, removing from it every speckled and spotted sheep and every black lamb, and the spotted and speckled among the goats, and they shall be my wages. So my honesty will answer for me later, when you come to look into my wages with you. Every one that is not speckled and spotted among the goats and black among the lambs, if found with me, shall be counted stolen.” Laban said, “Good! Let it be as you have said.”

In the Near East, sheep and goats are almost always a solid colour, usually white for sheep, and black for goats. Any speckled or spotted animals are a minority. Jacob is proposing that he gets to keep all the uncommonly patterened sheep and goats, and Laban gets to keep the rest. Laban is, of course, delighted, because he knows with this agreement, Jacob will get a very small minority of the flocks, and Laban will continue to get cheap (and good) labour out of Jacob. So Laban agreed immediately.

Laban isn’t stupid, he knows that if a solid-coloured sheep mates with another sold-coloured sheep, the offspring will almost always be solid coloured. However, if a solid-coloured sheep mates with a speckled sheep, for example, then there’s a good chance that the offspring might be speckled. Being the cheater that he is, Laban made sure that his flock will produce as few unusually coloured offsprings as possible. He took out all the “male goats that were streaked or spotted, all the female goats that were speckled or spotted (all that had any white on them), and all the dark-colored lambs.” (Gen 30:35–36) He had his sons care for these uncommonly coloured animals, keeping them away (a distance of three-days travel) from the rest of the flock. This will minimise any chance of the flock producing spotted, striped, or dark-coloured offspring; i.e., Laban is making sure that Jacob gets as few animals as possible.

From archeological and historical sources, we know that a contract between an owner and a shepherd usually provides for the shepherd to be paid 10% to 20% of the flock (and also some percentage of the wool and milk from the flock). Animals with unusual colours usually comprise less than 10%–20% of the flock, so Laban is definitely getting the better end of the deal.

So what do we have so far? Laban took out all the unsually coloured animals from his flock, and handed these over to his sons to care for. For the rest of the flock (all normally coloured animals), Laban asked Jacob to care for them. Laban also asked his sons to go a distance of three days distance from Jacob; this will make sure none of the unsually coloured animals might accidentaly mate with the normally coloured anmials.

Genetics

Why are some sheep white, and others are spotted? Why are the spotted ones in the minority? To find out, we need to look at genetics.

Let’s make things really simple and assume we’re looking at white and spotted sheep only^[2]And even then, it’s probably still overly simplified.. Sheep have a gene for colour, the dominant variation^[3]The variation in a gene, like W or w, is called an allele. of the gene, call it W, codes for white. There’s a variation of this gene that codes for spotted, call this w. Each sheep gets two sets of DNA^[4]Sheep, like humans, have cells that are called diploid, i.e., with two sets of DNA., one each from its parents. So for the “colour gene”, there will be two alleles, one from the mother, one from the father. It’s the combination of the two alleles that determines what the sheep’s coat will look like. W is “dominant”, i.e., if it’s found in the sheep’s DNA, the sheep will have a white coat. The other allele, w, is called “recessive” in the sense that if only one parent has it, the sheep will still show white. The following table is probably easier to understand:

Imagine a male and female sheep, both with the colour gene of Ww. This means the male received a W from one of its parents, and a w from the other; same for the female. When they mate, the offspring will have one of the possible combinations shown in figure 1 above. Note that both parents have Ww, and since W is dominant, both parents will have white coats, even though they both carry the w allele. The offspring will have 75% (3/4) chance of being white (either WW or Ww), and 25% (1/4) of being spotted (ww). The spotted characteristic is recessive, and the offspring will show spotted only if it received w from both parents^[5]The genetic makeup of an animal is called its genotype, but what we see as the animal’s appearance is called its phenotype (pheno is from the Greek word meaning “showing”). So in … Continue reading.

Jacob’s Problem

Enough genetics. Back to Jacob’s situation. If we continue with our limited example, we can see that Laban took away all the spotted sheep and handed them to his sons to keep, leaving Jacob with a flock of entirely white sheep. In terms of genotypes, it means Laban took all the sheep with ww for colour, leaving Jacob with WW or Ww sheep. Can Jacob get spotted sheep from this all-white flock? Yes, he can. All he has to do is let a Ww mate with another Ww, then there will be a 25% of having a spotted offspring. The problem then is how would he know which sheep are Ww? Remember there are no DNA tests back then (at least not that we know of).

The Bible describes what Jacob did:

Genesis 30:37–39 ESV

Then Jacob took fresh sticks of poplar and almond and plane trees, and peeled white streaks in them, exposing the white of the sticks. He set the sticks that he had peeled in front of the flocks in the troughs, that is, the watering places, where the flocks came to drink. And since they bred when they came to drink, the flocks bred in front of the sticks and so the flocks brought forth striped, speckled, and spotted.

It seems that by setting up the peeled sticks (the peeled sticks would look like striped or spotted animals), Jacob is able to cause the flock to breed striped and spotted offsprings. This certainly sounds like folklore or magic, and if Laban (or his sons) saw what Jacob is doing, they would not think it’s weird, because they most likely know of the same tradition. When Laban sees that this magic seems to work (because Jacob keeps getting more and more spotted animals), he’d think Jacob is particularly lucky. But I think the Bible provided another explanation.

God’s Solution

Further along in Chapter 31, Jacob was telling his wives:

Genesis 31:10–12 ESV

In the breeding season of the flock I lifted up my eyes and saw in a dream that the goats that mated with the flock were striped, spotted, and mottled. Then the angel of God said to me in the dream, ‘Jacob,’ and I said, ‘Here I am!’ And he said, ‘Lift up your eyes and see, all the goats that mate with the flock are striped, spotted, and mottled, for I have seen all that Laban is doing to you. (I added the bold)

I think the key sentence is in Gen 31:12a: God was telling Jacob which of the animals are striped, spotted, and mottled (have the Ww alleles). Jacob only need to follow God’s indication, and mate the Ww animals with each other, and not allowing any of the WW animals to participate. The offspring of a Ww will have one in four chance of being spotted (ww alleles), in which case Jacob would remove these spotted animals away from the rest of the flock (that’s exactly what he did in Gen 30:40). He’d continue breeding the ww animals with each other^[6]Two parents both with ww alleles would have all offsprings coming out 100% ww., while keeping the WW apart. This way, in a few years^[7]Sheep breed about once a year, sometimes less. The lambs are mature enough to breed the next generation when it’s only 5 months old, but probably 8 months or so is better. See for example, … Continue reading, most of Laban’s flock would be spotted, with only a minority of whites.

Conclusions

I don’t think Jacob followed any superstitious folk traditions or used any sympathetic magic to outsmart his uncle Laban. Jacob did set up the sticks to pretend he’s following superstition, but it was only a ruse to hide what he’s doing from Laban. Everything he did had good scientific explanations, the only exception was he got help from God telling him which of the animals carry the recessive gene.

So in conclusion:

1. No magic involved.
2. What happened is perfectly in line with the scientific principles of genetics.
3. Jacob did get help from God in order to identify the proper animals to breed.

Other Things

Stronger and Weaker Animals

In Gen 30:41, we read that Jacob is able to separate the stronger animals from the weaker ones. Since Jacob wanted to have spotted sheep, this would imply that the stronger animals are Ww. One possibility is that heterozygotes (an animal having different alleles for a gene, like Ww; those with the same allele, like WW or ww, are called homozygotes) are stronger, or at least breeds faster or earlier. But I wasn’t able to find definitive answers for this.

Laban the Cheater

In Gen 31, when Jacob was discussing with his wives about leaving Laban, it was six years after Gen 30 (where the supposedly magic with the sticks was described). During these six years, Laban changed his agreement with Jacob ten times (Gen 31:41). Why? Because Laban is a cheater. When he saw his nephew getting all spotted sheep, he’d change the agreement (“Oh, did I say that? No, no, no, my bad, I actually meant all the spotted sheep should belong to me!”) Of course, as soon as Laban made the change, Jacob would work with God (and genetics) to ensure the next generations of the flock turn out in favour of Jacob. We can imagine the frustration of Laban and his sons. Also, keeping Jacob at a distance of three days travel made it easier for Jacob to carry out the genetic manipulation without Laban figuring things out (setting up the peeled sticks, etc., also helped to hide what’s really happening).

Jacob’s Sheep

In recent news (2016), there’s a Jewish couple in Abbotsford, British Columbia, who raised a breed of spotted sheep named Jacob’s Sheep. The genetic markers of this breed can be traced back for thousands of years to the Middle East, starting in Syria (the home of Laban!) From Syria, it went down to Africa, then into Spain, Europe, and the UK, finally ending up in North America. The breed is named after Jacob and the story that we’re reading about in Gen 30–31. The couple wanted to bring the flock to Israel, because this breed has disappeared from Israel since biblical times. You can read about this on the CBC page, as well as many other news sites (just look up “Jacob’s sheep”).

Epigenetics

In recent years, there’s been much interest in something called epigenetics. Here’s a definition from the CDC ^[8]See also Epigenetics (nih.gov), as well as many other similar sites. The NIH page is considering epigenetics from the angle of being able to surpress genes that cause diseases like cancer.:

Epigenetics is the study of how your behaviors and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.

What is Epigenetics? | CDC

Maybe Jacob’s peeled sticks might have an effect on the breeding, as described by epigenetics. If so, then maybe the sympathetic magic that’s common folklore and tradition also have a grain of truth.

References

Duguid, Iain M. 2002. Living in the Grip of Relentless Grace: The Gospel in the Lives of Isaac and Jacob. Edited by Tremper Longman III and J. Alan Groves. The Gospel according to the Old Testament. Phillipsburg, NJ: P&R Publishing.

Mathews, K. A. 2005. Genesis 11:27–50:26. Vol. 1B. The New American Commentary. Nashville: Broadman & Holman Publishers.

Strassner, Kurt. 2009. Opening up Genesis. Opening Up Commentary. Leominster: Day One Publications.

Walton, John H. 2001. Genesis. The NIV Application Commentary. Grand Rapids, MI: Zondervan.