Your baby has reddish hair because they inherited the gene for red hair from both parents.
Here's a more detailed explanation:
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Genetics of Red Hair: Red hair is primarily determined by a gene called MC1R (melanocortin 1 receptor). This gene provides instructions for making a protein that helps determine skin and hair color.
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Recessive Inheritance: The gene for red hair is recessive. This means that a person needs to inherit two copies of the red hair gene (one from each parent) to actually have red hair.
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Carriers: If a person only inherits one copy of the red hair gene, they won't have red hair themselves. However, they are considered a "carrier" of the gene. They can pass this gene on to their children.
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How it Works:
- If both parents have red hair, their child will definitely have red hair.
- If neither parent has red hair, but both are carriers, there's a 25% chance their child will inherit the red hair gene from both of them and have red hair.
- If one parent has red hair and the other is a carrier, there's a 50% chance their child will have red hair.
- If one parent has red hair and the other doesn't carry the gene, their child will not have red hair but will be a carrier of the red hair gene.
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You Don't Need Red Hair to Pass it On: Even if you and your partner don't have red hair, you can both still be carriers of the recessive MC1R gene. This means you both carry the "red hair" DNA but it's not expressed in your own hair color. When both parents are carriers, the baby may inherit the red hair gene from both, resulting in reddish hair.
Therefore, the presence of reddish hair in your baby indicates that they inherited the recessive MC1R gene from both you and your partner, even if neither of you visibly display the trait.
