Trying To Cheat

Genesis 30:37-43

After twenty one years of being taken advantage of, Jacob felt he deserved proper some reward for his labor. Though he had a workable understanding of genetics, he was also familiar with an old wives tale that things the mother saw could influence physical characteristics of the baby. The same tale persists in many areas today. Jacob had proposed his offer to Laban, hoping that it would turn out to be true.

“And Jacob took him rods of green poplar, and of the hazel and chestnut tree; and pilled white streaks in them, and made the white appear which was in the rods. 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.” (Genesis 30:37-38)

Selective breeding depends on selecting the individuals having the desired characteristics and mating them. As we learn form Mendel’s work, initially the ratios of desired characteristics will remain fairly constant, but as time goes on, if only those who possess the desired characteristics are allowed to breed, the number offspring with other characteristics will decrease, eventually becoming quite rare. This is the system by which purebred breeds are derived. Many generations are required to develop a pure strain.

With an incomplete knowledge of genetics, Laban believed that separating the off colored cattle would result in a purebred strain immediately. Jacob had observed that not all the offspring bred true, and since he didn’t know why, he accepted the old wives tale and tried to use it to influence the outcome, by setting multicolored objects in front of the healthiest cattle.

“And the flocks conceived before the rods, and brought forth cattle ringstreaked, speckled, and spotted. And Jacob did separate the lambs, and set the faces of the flocks toward the ringstreaked, 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.” (Genesis 30:39-40)

The percentage of off colored cattle was high enough that Jacob was convinced his strategy was working and he continued it, while being very careful to separate the off colored ones to his own herd. He did not deliberately cross breed the off color ones with Laban’s.

“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. But when the cattle were feeble, he put them not in: so the feebler were Laban's, and the stronger Jacob's. And the man increased exceedingly, and had much cattle, and maidservants, and menservants, and camels, and asses.” (Genesis 30:41-43)

Mendel’s law tells us that in a genetic pool, the ratios of different charateristics will remain the same unless something prevents breeding of some of the characteristics, which is what selective breeding does. Because solid colored cattle were only a small part of the herd, often even those with solid colors also carried mixed color genes. Initially there would be more mixed colors than solids. It wasn’t long before Jacob’s cattle outnumbered Laban’s, and he began to be known as a cattleman himself.

Selective breeding inevitably reduces the genetic pool in other areas beside that of the desired characteristics, and in general, purebred animals are more susceptible to genetic defects and disease than mixed breeds. It wasn’t long before the difference in health began to show up. Believing his efforts were producing the results, Jacob kept them up for about six years. It would not have been long enough to have produced a truly purebred herd, as only about three generations of cattle would have been born.