Question

How do heritable genetic information (DNA) and environmental conditions contribute to the phenotype of a quantitative trait such as human height? (10 pts)

Answer 1

Ans- 1. Height and other phenotypic characters are controlled not only one gene but also multiple genes that contribute small distribution these phenomenon of inheritance is known as polygenic inheritance.

2. Recent study found about 400 genes linked to variation in height.

3.In these mechanism large number of gene involved, it is difficult to distiguish the effect of each perticular gene.

4. In addition to height does not depend on gentics but its also depend on  environmental factors that is overall health and type of nutrotion we get in growth time.

5. Human characters like height, color of eye, hair color show slight variation from one person to another these traits are controlled by many genes.

6 human polygenic traits are more complicated because of hundreds of different allelic pairs are involved in these inheritance.

7. Phenotype of organism shows variation becasue of enviornment factors.

8. One example shows how environment can affect phenotype that is herediatory disorder phenylketonuria (PKU). Those people homozygous for allele of disease  of PKU gene lack activity of enzyme. These enzyme breakdown phenylalanine amino acids.

9. It shows rapid increase in toxic level in their bodies.

10. Hence, human height is not only depend on genes it also depend on different envionmental factors, that is polygenic inheritance.