Why do you get black sheep and white sheep?

Answer 1

You get the color because of breeding the correct color sheep to each other. With the advent of pigments, white wool was selected for over black as it took dyes much better than other colors. While white sheep are still prevalent, many spinners are looking more to natural colored wools so a variety of sheep colors are making a comeback in handspinning wool circles.

Answer 2

Color genes and pattern genes have something to do with getting black and white sheep.

Usually a lamb inherits 2 genes for color, one from each parent. Those color genes causes the pigment named eumelanin to be produced in the cells of the wool follicles which can produce the basic black or brown color.

On the other hand, lambs carry 2 genes for PATTERN. There are 6 different patterns that can turn off the production of eumelanin pigment in the wool follicle cells in the entire body or certain parts of the skin on the body.

Turning off eumelanin pigment production in a certain part will result to color combinations or other pattern. Turning off eumelanin pigment production in the entire body will produce a white pattern.

Being white (or a pattern with absence of color) is considered a PATTERN and not a COLOR. When the animal carries this white pattern gene, it turns off all of the color-producing cells in the wool follicles. As the result, white pattern gene nullifies the basic color gene making the animal to appear white though the actual color (based on color gene) may be black or other colors. The actual color of such animal with "white pattern" may be determined by the color of the offspring.

Quite confusing but pretty amazing!