Question

1. The percentage of MZ twin pairs studied concordant for mental retardation is 97%, while the concordance of this trait in DZ twins is 37%. Assuming that both twins in each pair were raised together in the same environment, what do you conclude about the relative importance of genetic versus environmental factors in this trait?

Answer 1

Answer ) We need to understand a few terms before we arrive at the answer.

MZ twins = monozygotic twins

whereas, DZ twins = dizygotic twins

Monozygotic twins are the two individuals that arise from the single zygote and hence 100% share the same genetic constitution.

whereas in Dizygotic twins, both the individuals arise from two different zygote hence their genetic constitution is the same, but yet because they are given birth from the same parents, they have a probability of sharing atleast 50 % of their traits, chromosomes.

Concordance means degree of similarity

In the question they told us that the concrodance when the MZ twins were tested for mental retardation was 97%

while the same for the dizygotic twins was 37%.

And these concordances were measured when the the twins were kept in environmental conditions

This suggests that the genetic constitution of the individual plays a major role in determination of the mental retardation of the individual as compared to the enviromment.

we can also put it across as

Even though environment and genetic interplay each other at every stage of life, the genetic lays down the blueprint, the environment can be made use to maximise the limit of the individual, but within the limits of the blueprint.

i hope i was able to help you with the answer ! :)