What type of natural selection is skin color?

Natural selection may favour dark skin everywhere, though to a lesser extent at higher latitudes. Darwin believed that racial differences in skin colour were caused by sexual selection. Available evidence suggests that in each society a lighter-than-average skin colour is preferred in a sexual partner.

What factors affect skin color?

The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis.

Does carotene affect skin color?

The surprising fact is eating too many carrots, or other foods high in beta-carotene, can cause a yellowish discoloration of the skin, according to the Dermatology Clinic at UAMS. This discoloration, a condition called carotenemia, is most noticeable on the palms and soles.

How many genes affect skin color?

genes and me » skin color. Human skin color is a “polygenic” trait, meaning multiple gene loci are involved in its expression. At last count, the International Federation of Pigment Cell Society has determined that there are a total of 378 genetic loci involved in determining skin color in human and mice.

How does carotene affect skin color?

Carotene is a lipochrome that normally adds yellow color to the skin. With elevated blood levels of carotene, the prominence of this yellowing is increased.

What are the 3 factors that determine skin color?

Skin Color/Condition Skin color varies considerably from individual to individual and is generally determined by the presence of melanocytes, carotene, oxygenated hemoglobin, and local blood flow. Melanocytes, found in the deep basal layer of the epidermis, contain brown granules called melanin.

Does carotene lighten skin?

Supplementation with beta-carotene (and increased dietary intake of fruit and vegetables) also produces an increase in the normal skin yellowness20–22—but not skin redness or luminance21—of Caucasian skin, and studies have shown that a somewhat yellower skin color is considered healthier and more attractive by both …

What does carotenoids do to the skin?

Carotenoids can stimulate collagen and elastin in the skin to increase its density, elasticity and firmness. In addition carotenoids can repair and regenerate these protein fibers after damage by UV light. Carotenoids help stimulate epidermal regeneration helping to soften and smooth skin.

Can carotenoids change skin color?

So it is that carotenoids can also affect the pigment of human skin. Excessive consumption of carotene can turn the outer layer of the skin orange, resulting in a jaundice-like, or orange-tinged appearance.

What causes skin to turn orange?

When high levels of beta-carotene are consumed, not all of the pigment is converted to vitamin A. Some of it is circulated in the blood stream. If these high levels are sustained for some time, the skin may begin to take on an orange hue, a condition known as carotenemia.

Why does carotene affect skin color?

According to dermatologist Melissa Piliang, MD, carotenemia is caused by having too much beta-carotene in your blood steam. You know beta-carotenes as the pigment in certain red, orange and yellow fruits and veggies. “Eating too many beta-carotene filled foods can turn your skin an orangey color,” explains Dr. Piliang.

Is skin color a product of natural selection?

In brief, skin color is the result of natural selection on 2 conflicting selection traits involving UV light from the sun and biochemical processes: Vitamin B9, more properly known as folic acid or folate.

How does sunlight affect the evolution of skin color?

Sunlight not only affects skin color from one day to the next; it also has affected the evolution of skin color among the peoples of the world. In this lesson, we’ll learn something about how the process of natural selection over many generations has protected peoples of the world from too much or too little sun exposure.

What is natural selection and how does it work?

Basically, natural selection is how groups of living things get better suited to their surroundings. With enough time natural selection can even lead to new types of animals. It also explains how humans with different skin colors can share a single ancestor. But How Does It Work?

How does natural selection affect the distribution of vitamin D?

As people moved to areas farther from the equator with lower UV levels, natural selection favored lighter skin which allowed UV rays to penetrate and produce essential vitamin D. The darker skin of peoples who lived closer to the equator was important in preventing folate deficiency.