Question

Human height has a heritability of 0.85. The average American adult has a height of 5 feet, 7
inches. The average American college basketball player is 6 feet, 2 inches tall. What is the
expected average height of Americans who had two college basketball piayers as parents?
a.5 feet, 9 inches
b. 5 feet, 11 inches
c.6 feet, 1 inch
d. 6 feet,2 inches
e.5feet,Tinches

Answer 1

. A more accurate, but simplified, the definition is this: Heritability is the proportion of this total variation between individuals in a given population due to genetic variation. This number can range from 0 (no genetic contribution) to 1 (all differences on a trait reflect genetic variation).

Fathers appear to determine the height of their child while mothers tend to influence how much body fat they will have, a study suggests. The work is ongoing, but researchers from the Royal Devon and Exeter Hospital say the initial results are clear - taller dads make longer babies

about 80 percent of an individual’s height is determined by the DNA sequence variants they have inherited, but which genes these variants are in and what they do to affect height are only partially understood. Some rare gene mutations have dramatic effects on height (for example, variants in the FGFR3 gene cause achondroplasia, a rare condition characterized by short stature). For most individuals, though, height is controlled largely by a combination of genetic variants that each has more modest effects on height, plus a smaller contribution from environmental factors (such as nutrition).

Because height is determined by multiple gene variants (an inheritance pattern called polygenic inheritance), it is difficult to accurately predict how tall a child will be. The inheritance of these variants from one’s parents helps explain why children usually grow to be approximately as tall as their parents, but different combinations of variants can cause siblings to be of different heights. Height is influenced by other biological mechanisms (such as hormones) that may also be determined by genetics, although the roles of these mechanisms are not fully understood.

In addition to genetic and biological determinants, height is also influenced by environmental factors, including the nutritional status of the mother during pregnancy, whether she smoked, and her exposure to hazardous substances. A well-nourished, healthy, and active child is likely to be taller as an adult that will be a child with a poor diet, infectious diseases, or inadequate health care. Socioeconomic factors such as income, education, and occupation can also influence height. In some cases, ethnicity plays a role in adult height, but studies on immigrant families have shown that moving to a country with better access to nutritious food, healthcare, and employment opportunities can have a substantial influence on the height of the next generation; this suggests that some differences in height between ethnicities are explained by non-genetic factors.

Polygenic Traits

Another exception to Mendel’s rules is a polygenic inheritance, which occurs when a trait is controlled by more than one gene. This means that each dominant allele "adds" to the expression of the next dominant allele.

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. There is also a wide range of skin colour across people. Skin colour is also a polygenic trait, as are hair and eye colour.

Polygenic inheritance often results in a bell-shaped curve when you analyze the population(Figure below). That means that most people fall in the middle of the phenotypic range, such as average height, while very few people are at the extremes, such as very tall or very short. At one end of the curve will be individuals who are recessive for all the alleles (for example, aabbcc); at the other end will be individuals who are dominant for all the alleles (for example, AABBCC). Through the middle of the curve will be individuals who have a combination of dominant and recessive alleles (for example, AaBbCc or AaBBcc).

The answer will be option a) we cannot completely provide the accurate figure for such a situation as it could be a possibility as its polygenic inheritance

An example such as given below :