Sunday, February 17, 2013

Fun With Genetics

Baby woke me up early today, so I spent the morning playing with him and thinking about dominant and recessive traits, because you need something to keep your mind busy while entertaining a human whose most exciting part of the day is when daddy disappears behind a blanket only to magically reappear a moment later with an exclamation of, "Peek-a-boo!"

So, let's talk genetics.

This is more or less how they work, granted it's been a long time since I took advanced biology, so bear with me. Dominance or lack there-of is the relationship between alleles. In dominant traits, one allele overpowers the expression of the other allele of the same category (ex. eye color).

If you break it down to mom's DNA and dad's DNA, there will be three possible outcomes; expressing the dominant trait, expressing the recessive trait, or carrying the recessive trait while expressing the dominant one. Some traits are super recessive, less likely to occur even against other recessive traits. Add in grandparent genetics and this gets a little harder to keep track of.

They play out something like this:
Dominant Trait ----------------- Recessive Trait
Brown Eyes --------------------- Blue Eyes, Gray Eyes, Hazel Eyes
Every Other Eye Color -------- Green Eyes
Brown Hair, Black Hair ------- Blonde Hair
Every Other Hair Color ------- Red Hair
Curly Hair ---------------------- Straight Hair
Widow's Peak ------------------ Normal Hairline
Dark Skin ----------------------- Light Skin
All Other Skin Color ---------- Albinism
Freckles ------------------------- No Freckles
Dimples ------------------------- No Dimples
Unattached Earlobes ---------- Attached Earlobes

Before Jude was born, Aaron and I played at guessing what he'd look like. Of the two of us, Aaron has the more dominant genes with his dark hair and his dark eyes. For ease, above I have color coded Aaron's genetic traits and Mine for comparison.

Thus we expected that Jude would probably be light skinned with brown eyes, brown curly hair with a widow's peak, dimples, unattached lobes, and maybe freckles later in life. When he got here we were mostly correct. He had Aaron's hairline, dimples, unattached lobes, light skin, eyes that seem to be suggesting they'll be brown, and while he's got straight hair now that could change as he gets a little older. However we were surprised to discover Jude is a ginger!

Have you ever tried to guess what your baby would look like? How accurate were your guesses?

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