Practice Flashcards
Flip to reveal answersIn a pedigree, what shapes are used for males and females?
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All 10 Flashcards — Pedigree charts
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Question
In a pedigree, what shapes are used for males and females?
Answer
**Square = male**, **circle = female**.
Question
In a pedigree, what does a filled (shaded) symbol mean?
Answer
The person is **affected** — they show the condition. A clear symbol means unaffected.
Question
What is a carrier?
Answer
An **unaffected** person who carries one copy of a recessive allele (e.g. genotype Dd) and can pass it on.
Question
How can you tell from a pedigree that a condition is recessive?
Answer
**Two unaffected parents have an affected child** — a dominant allele cannot hide in an unaffected parent.
Question
How can you tell from a pedigree that a condition is dominant?
Answer
The trait appears in **every generation** (no skipping) and affected children usually have an **affected parent**.
Question
How does a pedigree show an allele is NOT X-linked?
Answer
A father gives his **X to every daughter** and his **Y to every son** — so an **affected son** or an **unaffected daughter** of an affected father means the allele is **autosomal**.
Question
An affected father passes which sex chromosome to a son, and which to a daughter?
Answer
His **Y** to a son; his **X** to a daughter.
Question
An unaffected woman has a child with an autosomal recessive condition. What is her genotype?
Answer
She must be a **carrier (Dd)** — heterozygous.
Question
What is the genotype of someone affected by an autosomal dominant condition (allele D)?
Answer
**DD or Dd** — at least one dominant D allele.
Question
What do the Roman numerals (I, II, III) on a pedigree show?
Answer
Each **generation**, oldest at the **top**.
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Full study notes for Pedigree charts
Topic 4.8 hub
Inheritance
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