Punnett Square: Interactive Case-Based Practice

Study these clues to infer inheritance patterns in the case activity below.
Pattern	Typical Clues	Example Traits	Genotype Notation Style
Autosomal Recessive	May skip generations; parents can be unaffected carriers; equal sex distribution.	Cystic Fibrosis, PKU, Tay–Sachs	Aa × Aa; Aa × aa
Autosomal Dominant	Seen in successive generations; affected parent passes to ~½ of offspring; equal sex distribution.	Huntington disease, Marfan	Aa × aa; Aa × Aa
X-linked Recessive	More males affected; carrier mothers; affected father → all daughters carriers, no sons affected (unless mother carrier).	Hemophilia A, DMD	XHXh × XHY; XHXH × XhY
X-linked Dominant	Affected fathers transmit to all daughters and no sons; affected mothers → ~½ of both sexes.	Rett syndrome	XAXa × XaY; XAXA × XaY
Incomplete Dominance	Heterozygote shows intermediate/blended phenotype.	Snapdragon color	RR (red), Rr (pink), rr (white)
Codominance	Both alleles fully expressed in heterozygote.	ABO blood group	IA, IB, i (e.g., IAi × IBi; IAIB → AB)
Mitochondrial	Maternal inheritance only; all children of affected mother affected; fathers do not transmit.	LHON	Maternal H/h passed to all offspring

Display:

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Click “New Case” to begin. The inheritance pattern is hidden; use the clues above.

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Tip: Click cells to cycle marks (Possible → Carrier → Affected → Unaffected → Clear). Right‑click to clear.

Enter Counts out of 4 (or switch to Percentages) and choose phenotypes from the menus.

Genotype	Count / %	Phenotype	Feedback
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Detected Pattern

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Recognizing Inheritance Patterns