Biology Inheritance Principle part 25 (Sex linked Inheritance) class 12 XII | Summary and Q&A

TL;DR

Sex-linked inheritance refers to genetic traits linked to the X chromosome, impacting the pattern of inheritance. Cross cross inheritance occurs when mothers pass traits to sons and fathers pass traits to daughters.

Key Insights

• 🕵️‍♀️ Sex-linked inheritance is when genetic traits are linked to the X chromosome and inherited differently in males and females.
• 🪽 Morgan's experiment with fruit flies demonstrated the presence of sex-linked inheritance.
• 🧭 Fathers cannot directly pass on sex-linked traits to their sons, but they can pass them on to their daughters.
• 😵 Cross cross inheritance occurs when mothers pass on traits to sons and fathers pass on traits to daughters.
• 😪 In the F1 generation of Morgan's experiment, all offspring were red-eyed, indicating dominant traits.
• 😵 Cross cross inheritance allows for the transmission of traits that may not be observed in immediate generations.
• 🕵️‍♀️ XX chromosomes result in female offspring, while XY chromosomes result in male offspring.

Transcript

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Questions & Answers

Q: What is sex-linked inheritance?

Sex-linked inheritance refers to genetic traits that are linked to the X chromosome, causing them to be inherited differently in males and females. These traits do not have a corresponding gene on the Y chromosome.

Q: How did Morgan discover sex-linked inheritance?

Morgan discovered sex-linked inheritance through his experiments with red-eyed and white-eyed fruit flies. He observed that certain inherited traits were exclusively present on the X chromosomes.

Q: What happens in the F1 generation of Morgan's experiment?

In the F1 generation, all offspring were red-eyed when red-eyed females were crossed with white-eyed males. This suggested that the red eye trait was dominant.

Q: How does cross cross inheritance occur?

Cross cross inheritance occurs when fathers pass on traits to their daughters and mothers pass on traits to their sons. This is because sons receive the X chromosome from their mothers and daughters receive the X chromosome from both parents.

Summary & Key Takeaways

• Sex-linked inheritance refers to genetic traits associated with the X chromosome and impacts the inheritance pattern.

• In Morgan's experiment, red-eyed females crossed with white-eyed males produced all red-eyed offspring in the F1 generation, indicating dominant traits.

• Cross cross inheritance occurs when mothers pass on traits to sons and fathers pass on traits to daughters, as seen in the inheritance of eye color.