Even More Genetics! and Pedigrees

In this class we delved even further into the topic of genetics, this time looking at pedigree's and how dominant genes work together, such as AaBb.  So first of all, how they work together, is when in the genes their is too dominant alleles, like in AaBb, then their can be a co-dominance.  In pheontypic terms, it could be a brown cow with white spots.  Both of the dominant traits for color will show up.  If the genes were Aabb though, the cow would be all brown.  It only takes one dominant gene to over ride the recessive traits.  On to pedigrees, these are family trees that put into picture what punnett squares do for us in genetics.  Their is seperate symbols for male: carrier, deceased, etc., female: carrier, deceased, pregnant, etc., and even unspecified gender for pregnancy.  So with these you then have the ability to make a detailed family trees which show the traits being passed on through many generations of breeding.

Genetics and Meiosis

In this class we furthered our knowledge of genetics with alleles, as mentioned in the previous blog, and looked at the process of meiosis.  Meiosis is the process of your parents genes copying half of their traits and creating a new cell, a sex gamete.  These sex gametes are only supposed to have 23 traits each so that when they meet there is 46, the offspring's traits.  I say "supposed to have" because sometimes occasionally an extra trait will be coded in to the gamete and this can cause genetic disorders such as down syndrome.  The 23 traits that go into each of your parent's gametes are random, your mom and dad could give b recessive for blonde hair but they both might have brown hair.  This is where the punnett squares come in, if they are both carriers then there is that 1/4 chance you will be recessive-recessive.  But if they had four children, there would not necessarily be 1 BB, 2 Bb, and 1 bb.  This is because the process of selecting genes is randomized, yes the percentage outcome is still fairly accurate but, it will not be exact in this situation.  This is how meiosis works, and this is how your parents passed on their genes to you.

First Day of Unit 4: Alleles

In this class we started the fourth unit which involves genetics and how they work.  This is important to us because it is us.  Genetics are what determine anything that is living.  They are what distinguish each of us as different people down to our sex.  So for this class we specifically looked at how genes are passed down form parents to their offspring.  Traits get passed on from your parents, one from your dad and one from your mom.  Let's take hair color as a n example: Let's say B is the dominant gene for brown hair and b is the recessive trait for blonde hair.  Now your parents both have two genes for this trait because they got one from each of their parents.  Lets say your parents Bb and bb.  That means you have a 50% Chance of being Bb and 50% chance of being bb in other words you could be brown haired or blonde haired.  Recessive traits like blonde hair in the example only show up if both of your genes are that, if a dominant allele is present whether it is one or two, will show.  That is why it is called the dominant gene.  The first person to see these alleles and apply them was Mendel who bread pea plants and observed generations and how certain genes would show in them.  He would look at height, color, etc. and see how these traits would pass through in generations of pea plants.  This is how humans and all animals differ from one to another.

Test Day

In this class we had our unit 3 test.  Talking mainly about DNA replication and protein synthesis. There was also previous concepts brought up sporadically like osmosis.  The test was challenging for me though, and it has shown me that I really do not understand DNA replication and protein synthesis.  These are two things I greatly need to review as we go into the next unit of genetics.  I know it is all the background to what we are about to study, but I have trouble grasping exactly how to do the processes on paper.  The steps are simple enough in both, but it is difficult to take a short strand and go through these steps all on paper.  The Unit test let me see where I need a lot of improvement.

Snorkitty Snork Snork

In this class we looked at the process of translation.  Translation is where RNA is read by a ribosome and transformed into proteins based on the coding in the RNA.  In this labs these proteins then show up as traits in mythical beings known as snorks.  Lovable, but dangerous creatures indeed.  We looked at a small strand of RNA that would hypothetically represent 9 main traits.  Every group was given a different strand of RNA so that everyone's snork would look different in the end based on their physical traits.  This is how it works in real creatures cells as well, but on a much larger scale.  For the snorks though, mine came out as such:

SNORK

Sweet Jumpin' Genes He Has 8 Fingers

 This picture may only show a flower bursting with a lovely lilac color, but really there is 100's of jumping genes at play forming a mutation.The color gene in this flower, purple or white (you can't assume it is one or the other), has jumped around the DNA either cutting itself from one part and going into another or duplicating, and sending the copy to another segment. With the movement of this gene a mutation forms making the flower splash with vibrant colors. At one point in previous generations of this type of flower, it may have been all purple or white.

In this lil' curly devil's genes there was a duplication because of a movement in the Zone of Polarizing Activity (ZPA).  When shifted this can cause a duplication of certain structures.  In this case it was fingers, the ZPA must have moved multiple times and created many fingers on accident. This is why this child has so many excess phalanges.  

Chapter 3 Summary

In this chapter of Your Inner Fish, the author delves deeply into why organisms develop the way they do and what separates them form any other living organism.  The answer to the second part of that is within the DNA; organisms may have extremely similar DNA but the relatively small variations make huge differences. This is because of development also, when an organism is first created it is very small and has DNA that can only form so many cells.  Those cells though, then form more and more and eventually what started as a single cell organism is a self-functioning creature.  So this is why creatures with similar structures differ so greatly in the big picture.  The next question that is answered is why creatures have symmetrical structures.   A breakthrough in research at a Harvard research lab explained why pinky's formed different from thumbs and why hands formed symmetrically.  The zone of polarizing activity (ZPA), was where the development was happening that would make a the hands.  If moved, a may form two identical digits.  Another project where the ZPA was secluded to half of a cell showed that the half with the ZPA developed a hand while the other side did not.  In the final part of the reading it explained that because of the way certain parts of genes in DNA are active at only certain times to make different types of molecules, even humans and fly's have similar genes for hands/wings, but they develop differently.  It argues that the changes through evolution did not necessarily come from new DNA, but rather ancient DNA that was not active in other organisms during their developmental stages.