is because of the human genetic code that a fertilised human egg grows into a human baby and cannot grow into an elephant, a bird or a mouse. Genetic transmission is very complex. Most characteristics that we observe in humans are combinations of larger number of genes. You can imagine the combinations produced by , or more genes – accounting for a variety of characteristics and behaviours.
It is also not possible to possess all the characteristics made available to us by our genetic structure. The actual genetic material or a person’s genetic heritage is known as genotype . However, not all of this genetic material is apparent or distinctly identifiable in our observable characteristics. Phenotype is the way an individual’s genotype is expressed in observable and measurable characteristics.
Phenotypes include physical traits, such as height, weight, eye and skin colour, and many of the psychological characteristics such as intelligence, creativity, and personality. These observable characteristics of an individual are the result of the interaction between the person’s inherited traits and the environment. You know it is the genetic code which predisposes a child to develop in a particular way. Genes provide a distinct blueprint and timetable for the development of an individual.
But genes do not exist in isolation and development occurs within the context of an individual’s environment. This is what makes each one of us a unique person. What are the environmental influences? How does the environment affect development?
Imagine a child, with genotype that predisposes her/him to be introverted, in an environment that promotes social interaction and extroversion. The influence of such an environment may make the child a little extroverted. Let us take another example. An individual with “short” height genes, even if s/he is in a very good nutritional environment, will never be able to be taller than average.
This shows that genes set the limit and within that limit the environment influences development. You know by now that parents provide the genes for the child’s development. Do you know that they also play an important role in determining the type of environment their