In an assessment of learning in Drosophila, flies were trained to avoid certain olfactory cues. In one population, a mean of 8.5 trials was required. A subgroup of this parental population that was trained most quickly (mean=6.0) was interbred, and their progeny were examined. These flies demonstrated a mean training value of 7.5. Calculate realized heritability for olfactory learning in Drosophila.

Verified step by step guidance

1. Identify the formula for realized heritability: \( h^2 = \frac{R}{S} \), where \( R \) is the response to selection and \( S \) is the selection differential.
2. Calculate the selection differential \( S \): \( S = \text{mean of selected parents} - \text{mean of original population} = 6.0 - 8.5 \).
3. Calculate the response to selection \( R \): \( R = \text{mean of progeny} - \text{mean of original population} = 7.5 - 8.5 \).
4. Substitute the values of \( R \) and \( S \) into the heritability formula: \( h^2 = \frac{R}{S} \).
5. Simplify the expression to find the realized heritability.

Key Concepts

Heritability

Heritability is a measure of how much of the variation in a trait within a population can be attributed to genetic differences among individuals. It is expressed as a ratio ranging from 0 to 1, where 0 indicates that genetics do not influence the trait, and 1 indicates that genetics are solely responsible for the variation. Understanding heritability is crucial for predicting how traits may be passed on to future generations.

Realized Heritability

Realized heritability refers to the proportion of phenotypic variance in a trait that is attributable to additive genetic variance, as observed in a specific population under certain environmental conditions. It is calculated using the formula: h² = R/S, where R is the response to selection (the difference in trait means before and after selection) and S is the selection differential (the difference between the mean of the selected parents and the overall population mean). This concept helps in understanding the effectiveness of selection in breeding programs.

Olfactory Learning in Drosophila

Olfactory learning in Drosophila, or fruit flies, involves the ability of these insects to associate specific smells with positive or negative experiences, influencing their behavior. This learning process is often studied to understand the genetic and neural mechanisms underlying memory and learning. The training trials mentioned in the question reflect the number of attempts required for the flies to learn to avoid certain odors, which can be quantitatively analyzed to assess genetic influences on learning capabilities.