Table of Contents
- 1 What is usually the cause of traits that show a wide variety of phenotypes such as skin tone and eye color?
- 2 Why there are a wide variety of phenotypes for skin color in humans?
- 3 Why do humans vary so much in skin color and height?
- 4 Why is human height a polygenic trait?
- 5 Why do areas of high altitude have greater than expected UV intensity?
What is usually the cause of traits that show a wide variety of phenotypes such as skin tone and eye color?
Multiple gene (polygenic) inheritance explains many plant and animal traits where there is a wide variation between extreme phenotypes, with most individuals having intermediate phenotypes.
Why there are a wide variety of phenotypes for skin color in humans?
There are a wide variety of phenotypes for skin color because of hybridization. The traits controlled by a recessive alleles on the X chromosome are more common in males than females. It is inherited by having a codominanant allele with the normal allele.
Which human traits are controlled by many genes?
Polygenic inheritance occurs when one characteristic is controlled by two or more genes. Often the genes are large in quantity but small in effect. Examples of human polygenic inheritance are height, skin color, eye color and weight.
Why do humans vary so much in skin color and height?
About 80 per cent of the normal variation in human height is the result of inherited genetic differences between people, with the rest of the height difference being due to environmental influences, such as diet or upbringing.
Why is human height a polygenic trait?
Usually, traits are polygenic when there is wide variation in the trait. For example, humans can be many different sizes. Height is a polygenic trait, controlled by at least three genes with six alleles. If you are dominant for all of the alleles for height, then you will be very tall.
How does the function of melanin explain the variety of skin colors?
Melanin is a type of pigment that gives color to the hair, skin, and eyes in humans and animals. In addition to providing pigmentation for the cells, melanin also absorbs harmful UV rays and protects against cellular damage from UV light exposure.
Why do areas of high altitude have greater than expected UV intensity?
Why do areas of High Altitude have greater than expected UV intensity and areas of constant cloud cover have less than expected? High Altitude places have more exposure to UV than low altitude because they are farther away from the sun. They are less likely to absorb the UV than the light skinned humans.