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Read Pleiotropy through Pathways
One gene can influence several phenotypic traits through connected pathways.
NSEJS · Principles of Inheritance and Variation · 1 linked question · 100% coverage
Know this first
Pleiotropy is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Study deeper: NCERT Science · Principles of Inheritance and Variation
Trace the downstream effects
A gene product can participate in an interconnected metabolic pathway; changing it may alter several traits. This is pleiotropy.
Epistasis and temperature-sensitive alleles
A dominant inhibitor can mask expression at another locus: only homozygous recessive inhibitor genotypes reveal the pigment locus. A temperature-sensitive enzyme is active only in a particular temperature range, so body regions or developmental stages can show different pigment expression.
OlympIQ exam lens
- ✓Pleiotropy = one gene affects multiple traits.
- ✓Dominant inhibition can mask a second gene.
- ✓Temperature-sensitive enzymes create location-dependent phenotypes.
OlympIQ trap
Do not confuse pleiotropy (one-to-many) with polygenic inheritance (many-to-one).
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