In Drosophila, the Genes for Body Coloration and Eye Size

question 109

Multiple Choice

In Drosophila, the genes for body coloration and eye size are on different chromosomes.Normal-colored bodies are dominant to ebony-colored (very dark) bodies, and normal-sized eyes are dominant to being eyeless.Line A is true breeding for normal body and normal eye, whereas line B is true breeding for ebony bodies and being eyeless.From a dihybrid cross between lines A and B, 480 flies are scored.How many F₂ flies are expected to have both ebony body color and to be eyeless?

• A) 1
• B) 30
• C) 90
• D) 120
• E) 270

---

Definitions:

Synaptic Pruning

A neurodevelopmental process where extra neurons and synaptic connections are eliminated to increase the efficiency of neuronal transmissions.

Neurogenesis

The process by which new neurons are formed in the brain.

Synaptic Reuptake

A process by which neurotransmitters are absorbed back into the neuron after being released into the synaptic gap, influencing the modulation of neural signals.

Inhibitory Postsynaptic Potential

A type of synaptic potential that makes a post-synaptic neuron less likely to generate an action potential.