Question

Частота конкордантності (співпадання) шизофренії у монозиготних близнюків складає 70%, дизиготних – 13%, епілепсії – відповідно 67% і 3%, кольору очей – 99,5% і 28%. а) Які з названих ознак мають лише спадкову детермінацію і які визначаються ще і факторами зовнішнього середовища? б) Визначте частку генетичного фактора у формуванні шизофренії, епілепсії і кольору очей.

Answer 1

9ʼ(6,9,1) так правильно

Answer 2

Frequency of Concordance (Coincidence) of Schizophrenia, Epilepsy, and Eye Color in Monozygotic and Dizygotic Twins

According to the provided information, the frequency of concordance (coincidence) of certain traits in monozygotic (identical) and dizygotic (fraternal) twins is as follows:

- Schizophrenia: 70% in monozygotic twins and 13% in dizygotic twins. - Epilepsy: 67% in monozygotic twins and 3% in dizygotic twins. - Eye color: 99.5% in monozygotic twins and 28% in dizygotic twins.

a) Which of the mentioned traits are solely determined by genetic factors, and which are also influenced by external environmental factors?

Based on the information provided, it can be inferred that schizophrenia, epilepsy, and eye color are influenced by both genetic factors and external environmental factors.

- Schizophrenia and epilepsy: While the concordance rates for schizophrenia and epilepsy are higher in monozygotic twins compared to dizygotic twins, indicating a genetic component, the fact that the concordance rates are not 100% suggests that external environmental factors also play a role in the development of these conditions. Therefore, both genetic factors and external environmental factors contribute to the manifestation of schizophrenia and epilepsy.

- Eye color: The high concordance rate of eye color in both monozygotic and dizygotic twins suggests that eye color is primarily determined by genetic factors. The concordance rate of 99.5% in monozygotic twins indicates a strong genetic influence, while the concordance rate of 28% in dizygotic twins suggests a lesser genetic influence and a greater role of external environmental factors in eye color determination.

b) Determine the proportion of the genetic factor in the development of schizophrenia, epilepsy, and eye color.

It is important to note that determining the exact proportion of the genetic factor in the development of these traits is a complex task influenced by various factors, including genetic and environmental interactions. The concordance rates provided for monozygotic and dizygotic twins can give us an indication of the genetic contribution, but they do not provide a precise measure of the proportion.

- Schizophrenia: The higher concordance rate in monozygotic twins (70%) compared to dizygotic twins (13%) suggests a significant genetic contribution to the development of schizophrenia. However, it is important to consider that environmental factors also play a role, as the concordance rate is not 100% in monozygotic twins.

- Epilepsy: The concordance rate of 67% in monozygotic twins and 3% in dizygotic twins indicates a substantial genetic influence on the development of epilepsy. Again, environmental factors are likely to contribute as well, as the concordance rate is not 100% in monozygotic twins.

- Eye color: The high concordance rates in both monozygotic (99.5%) and dizygotic (28%) twins suggest a strong genetic influence on eye color. However, the lower concordance rate in dizygotic twins indicates that external environmental factors also play a role in determining eye color.

In summary, while the concordance rates in monozygotic and dizygotic twins provide evidence for the genetic contribution to the development of schizophrenia, epilepsy, and eye color, it is important to recognize that these traits are influenced by a combination of genetic and environmental factors. The exact proportion of the genetic factor in each trait's development is difficult to determine precisely.