God had revealed to Jacob how to get the most from Laban's herds by asking for the dominant genes (marked animals) which would emerge in the offspring of the recessive gened animals (unmarked). This story shows that God knew about genetics before Mendel and revealed some of it to Jacob. See Genesis 30:32 and 31:10-12.
Jacob didn't have full confidence in God's plan and decided to try to help it along with some primitive ideas of his own.
Knox Free Church,
Perth, Scotland GB
His Name forever shall endure;
last like the sun it shall:
Men shall be blessed in Him,
and blessed all nations shall Him call (Ps. 72:17)