Question

1. Since we are all so closely related, it is amazing that we see such tremendous diversity in the human population. List three reasons why phenotypic traits such as skin color, eye color or collagen production can vary so widely. For each reason you state, you must fully describe how that particular genetic phenomenon works. Please answer in detail.

Answer 1

Phenotype describes all aspects of the individual's morphology, physiology, behavior, and ecological relations. phenotypic traits such as skin color, eye color or collagen production can vary so widely.

Traits are characteristics or features that can be transferred from one generation to another. Phenotypic traits include physical characteristics like eye colour, height , hair colour etc.

We all human being have developed through evolution and we have acquired similar traits from generations but we are not similar or clone of each other. These variations come from:

1. DNA

The variations depend on DNA from our parents.

It depends on which half of the genetic information is given by each parent

Half of mothers chromosome (23) and the other half from fathers chromosome (23) which will constitute the complete set of an offsprings chromosome( 46)

1. Mutations

There are different types of mutations that occur in the DNA sequence. These can be beneficial or harmful. Changes in DNA that is passed on to the next generation causing difference in proteins can cause variations.

Beneficial mutation: example skin colour , according to protection needed from UV rays. Harmful mutation: certain diseases like Down syndrome.

1. Environmental

Environmental factors are certainly critical in defining phenotypes during early development

When we grow, our development and behavior are affected by- personal experiences we gain through our environment and our genetic makeup.

Example: Diet provides us nutrition, this nutrition is incorporated to the body by genes.

Environmental factors can affect and alter gene expression.

Genes can define how we respond to different environments.

Another example of 2 twins study gives that:

Identical twins, the products of a single fertilized egg that divided and produced two complete babies with identical genes. Suppose after their birth they are separated and start growing in two different countries, they will start learning different cultures of that particular country and will start acquiring that character, behavior, culture, and diet.

Although the twins were born with identical genetic properties, the different cultural environments in which they live will produce differences between them.