Biology

1: Key Observations:

Affected individuals are shaded gray.
The mother in the first generation is affected (gray circle).
The father in the first generation is unaffected (white square).
Among their offspring, only the sons are affected, while both daughters are unaffected.

2: Analysis:

X-linked dominant: This is unlikely because, in an X-linked dominant inheritance, an affected mother would pass the disorder to both sons and daughters, as she passes one of her X chromosomes to all her children.
However, in this chart, the daughters are unaffected.

X-linked recessive: This is the most likely explanation.
The mother is a carrier for the disorder (), and the father does not have the disorder (

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