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Question #45506
The Question
A hypothetical mutant strain of Commelina exclusively produces cleistogamous flowers. Despite hundreds of generations of obligate autogamy, the strain maintains high vigor and does not exhibit severe inbreeding depression. Which of the following genetic conditions most likely serves as an evolutionary buffer against the accumulation of deleterious homozygous alleles in this strain?
Options
- A.
Aneuploidy, which introduces novel functional genes through non-disjunction.
- B.
Polyploidy, which provides gene redundancy to mask deleterious recessive mutations.
- C.
High frequency of crossing over during microsporogenesis within the closed buds.
- D.
Dichogamy, which prevents the simultaneous maturation of anthers and stigma.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Cleistogamy vs Chasmogamy|Outbreeding Device Logic|Aneuploidy vs Polyploidy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'cleistogamy leads to inbreeding depression' without understanding the underlying mechanism (homozygosity of deleterious recessives).
The trap is assuming crossing over (Option C) can prevent inbreeding depression in obligate selfers.
The synthesis requires recognizing that polyploidy's gene redundancy is a classic evolutionary mechanism allowing highly selfing plants to survive the genetic load that would otherwise cause extinction.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Cleistogamy vs Chasmogamy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |