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Posts Tagged ‘pathophysiology’

Because I have been spending so much energy on this genealogy thing lately, I have not been attending to my studies as I should. I was sitting in pathophysiology class last night daydreaming about family history. We were discussing congenital and genetic disorders. The subject of the first part of the lecture was mendelian genetics and inheritance. (It was a review for me so I felt ok about daydreaming.)

 

<boredom alert> 

 

In a nutshell, each one of us has two chromosomes, one contributed by mom and one contributed by dad, for each trait we inherit. Some chromosomes are naturally dominate. Let’s consider eye color. Brown eyes are dominate, blue eyes are recessive. In order for you to have blue eyes, both parents have to carry the recessive chromosome and pass it along to you. (Gregor Mendel didn’t know about chromosomes and genes so he called them alleles or traits, same thing for our purposes.) Let B represent the trait for brown eyes and b represent the trait for blue eyes.

BB represents someone that inherited the brown-eyed trait from both parents. This person has brown eyes.

bb represents someone that inherited the blue-eyed trait from both parents. This person has blue eyes.

Bb represents someone that inherited both traits from their parents, one from each. This person has brown eyes (they’re dominant) but also carries the blue-eyed trait that can be passed along to their children (the grandchildren).

 

I’m still daydreaming but now I’m watching the professor drawing on the whiteboard.

 

When calculating the probability of producing a brown-eyed child or a blue-eyed child, it starts to look like this.

 

BB   +   BB   =>   BB   BB   BB   BB

Both parents have brown eyes with no recessive trait for blue eyes: 100% of their offspring will have brown eyes, none are able to pass along blue eyes to their children.

 

bb   +   bb   =>   bb   bb   bb   bb

Both parents have blue eyes with no dominate trait for brown eyes: 100% of their offspring will have blue eyes, none are able to pass along brown eyes to their children.

 

Bb   +   BB   =>   BB   BB   Bb   Bb

Both parents have brown eyes, one carries the recessive trait, one does not: 100% of their children will have brown eyes with 50% inheriting the recessive trait for blue eyes.

 

Bb   +   Bb   =>   BB   Bb   Bb   bb

Both parents have brown eyes, both carry the recessive trait: 25% of their children will have brown eyes with no recessive trait, 50% of their children will have brown eyes with the recessive trait, 25% will have blue eyes.

 

Bb   +   bb   =>   Bb   Bb   bb   bb

One parent has brown eyes and carries the recessive trait, one parent has blue eyes: 50% of their children will have brown eyes with the recessive trait, 50% will have blue eyes. (Here are the light Jordans and the dark Jordans, 50/50.)

 

Here’s where I actually become engaged in the lecture.

 

James Jordan, according to the family oral history, was fair, red-haired and blue-eyed. Martha was darker, raven-haired and brown-eyed. Some in the family say Martha was native american indian. If she was 100% indian, the children would have all looked like her because she wouldn’t have carried the recessive traits for blue eyes and red hair.

A few years ago, another researcher provided some info on Martha’s family. Supposedly, (I say supposedly because I have no evidence as yet. I’m still stuck in Arkansas and Texas.) her father was Robert Bull, a physician of English descent. Her mother was Susannah Sullivan, the daughter of a man named Sullivan and a Creek mother. This makes sense and validates Aunt Jip’s claim that the Bulls were English. It also validates the story that Martha was indian.

I’m taking notes now. This is strictly speculation.

 

                               Sullivan father          Creek mother

                most likely Bb or bb          +          BB   (Is Sullivan Irish?)

                                                         ~

                   Robert Bull         Susannah Sullivan

   most likely Bb or bb      +       BB or Bb   (Most likely Bb if dad was bb.)

                                        ~

James Jordan          Martha Bull

         bb            +            Bb       

                         ~

9 children – roughly half resembling Jim and half resembling Martha

 

The big question is, did Martha have siblings with blue eyes or were they all brown-eyed? This is where my esteemed professor, while still lecturing, wandered to the back of the room and glanced over at my notes. Was I the only one writing furiously? <nervous grin>

I think I’m ready for the exam now.

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pathophysiology keeping me up at night

Can’t sleep…can’t think…can’t function…exam today. I am in pathoverload. The first exam predisposes to a particular sort of stress induced psychosis. Can’t even come up with eye candy for ww. Here’s an amusing link. adopt a microbe

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