Ever wanted to learn a foreign language?

[NewbieChris]

She's happy she got an A, she doesn't settle for anything less, lol :)

I live by the philosophy "D's get Degrees"

[dna9488]

Hey Shibby, didn't u say your wife was in Med school???

[Shibby]

She will finish her bio undergrad the end of the summer and will start biotech masters in the fall.

[dna9488]

She will finish her bio undergrad the end of the summer and will start biotech masters in the fall.

AHHHH, ok ok. I was thinkin about majoring in bio, but when i had my highschool experience of chem i loved it. So throughout high school i was on the Chem Team, and now i am majoring in Chemistry.

Dude can you please ask her a question from me: what in the hell is "The Chromosome Theory of Heredity"? its in my genetics book and it doesn't make sense. The only concept i learned from it was hemizygote.

[Shibby]

She said she will post about it tomorrow, she is kind of busy tonight with her own stuff. I told her that her obligation is to the board first, but she just laughed at me :(

[dna9488]

She said she will post about it tomorrow, she is kind of busy tonight with her own stuff. I told her that her obligation is to the board first, but she just laughed at me :(

haha. I don't want to rush her if she is busy. If she has better things to do tomm, than don't worry about, no big deal. Appreciate the help though.

[magdalena]

To make both of you happy ... :)

In order to understand the theory you are talking about it is essential to understand Mendel's Laws.
During meiosis, the cell undergoes many divisions: in meiosis I you have Prophase, Methaphase, Anaphase, and Telophase. Here you will have two daughter cells that are different (the main point of meiosis I is to separate homologous chromosomes)In meiosis II you have pretty much the same, but the outcome gives you 4 daughter cells that have totally different genetic makeup (the point of meiosis II is to separate sister chromatids).
Each chromosome contains genes that are located in certain manner. During meiosis (some books say that it is during late Prophase) a cross over can occur between sister chromatids and when they are pulled apart in telophase II, they create different genetic outcome.
If you go back to Mendel, the idea of the chromosomes is simple. If you have two chromosomes that are the same, you create homozygote. If you have a variation, you create a heterozygote. Let use an example, let say that blue eye color is coded by BB and brown color by bb. If you cross the parents that are homozygous for blue and brown eyes (which is two alleles that are the same, BB or bb) the offsprings will be all blue eyed since I designated blue eye color as dominant and this one will be expressed in all the offsprings.
T.H.Morgan made some interesting studies with eye color in fruit fly. "Crossing of a white-eyed male fly with a red-eyed female. The offspring were all red-eyed, but the second generation was 75% red-eyed and 25% white-eyed. Furthermore, the white-eyed flies were all male, and there were twice as many red-eyed females as red-eyed males"(The Path to the Chromosome Theory of Heredity).
The support for this theory is that presence of disjunction. If the chromosome doesn't separate from its homologous chromosome or the sister chromatids don't separate you end up with monosomy which can give you problems like Turner syndrome. If there are more chromosomes, you end yo with trisomy, or monosomy and an example would be Down syndrome.
The take home message would be that Sutton and Boveri combined Mendel's work, added chromosomal behavior to it and named it The Chromosome Theory of Heredity/Inheritance.
Where heterozygous chromosomes (XY) will give you a male which is totally different from homozygous (XX) female.

Sorry for throwing so much at you, if anything is unclear just let me know, I will try to do better job explaining. I am just not sure how much genetics you know, so I left it as you have a pretty good idea of what is going on. Hope that helps.

[Shibby]

hahahahaha, I didn't understand most of it. I hope you do :D

[Bouncer]

also shib, rado can teach you Spanish if you ask him nice. lmao

[Bouncer]

hahahahaha, I didn't understand most of it. I hope you do :D

i will explain it to you tomorrow. i dont have time for small minds now. :)

[dna9488]

OMG Magdalena, YOU ROCK. Thank you so much :) I didn't know you were Shibby's wife until now, haha. Ya this makes sense. You basically reinforced what my book said and made the information that wasn't clear, clear. reading about disjunction was interesting. So basically if one of the chromosomes doesn't disjoin, the progeny will have an abnormal count of chromosomes and die eventually? Half this chapter goes over the crosses between the white-eyed and red-eyed Drosophila.


One more ques i have is, can you explain what does Nullo-X mean
Also, i have provided a diagram, and I wrote what my explaination of that diagram. Can you read and see if what i am saying makes any sense at all? I am very sorry for the inconveience. Thanks again.


here is my explanation:
Non-disjunction is when there is failure of the X and Y chromosomes to disjoin during meiosis. When this happens the resulting progenies are either sterile or fertile. In Figure 5.6, there is a cross between white-eyed female Drosophila and red-eyed male Drosophila that is hemizygote. The female’s alleles are ww and the male is w+. What happened was one of the X chromosomes from the female didn’t disjoin, and the offspring now have abnormal counts of chromosomes. One of the offspring’s is a XX red-eyed mail with w and w+ alleles. The wild-card allele gave him the red eyes. Another offspring is a female that will die because its sex chromosomes are XXX with www+ alleles. Another offspring is a red-eyed male with a XO sex chromosome, and has a wild-card allele. There is also a white-eyed male offspring that is hemizygote with the sex chromosomes as XY, and a w allele. Another offspring is a white-eyed female with XXY sex chromosomes, and ww alleles. Lastly, there is a dead offspring because it has the YO chromosome. The reason it dies is because it needs one X chromosome to live, and the O means an absence of a chromosome.

[dna9488]

hahahahaha, I didn't understand most of it. I hope you do :D

OMG dude this helps out soo much. You have no idea. Now i can walk into class Monday for a quiz and ACE the hell out of it.

I walked into this class the 1st day enjoyin it. Genetics is very interesting and I want to be able to use in the future and even explain some of in BB.

You have a great wife, you should be very happy :)

[Shibby]

OMG Magdalena, YOU ROCK. Thank you so much :) I didn't know you were Shibby's wife until now, haha. Ya this makes sense. You basically reinforced what my book said and made the information that wasn't clear, clear. reading about disjunction was interesting. So basically if one of the chromosomes doesn't disjoin, the progeny will have an abnormal count of chromosomes and die eventually? Half this chapter goes over the crosses between the white-eyed and red-eyed Drosophila.


One more ques i have is, can you explain what does Nullo-X mean
Also, i have provided a diagram, and I wrote what my explaination of that diagram. Can you read and see if what i am saying makes any sense at all? I am very sorry for the inconveience. Thanks again.


here is my explanation:
Non-disjunction is when there is failure of the X and Y chromosomes to disjoin during meiosis. When this happens the resulting progenies are either sterile or fertile. In Figure 5.6, there is a cross between white-eyed female Drosophila and red-eyed male Drosophila that is hemizygote. The female’s alleles are ww and the male is w+. What happened was one of the X chromosomes from the female didn’t disjoin, and the offspring now have abnormal counts of chromosomes. One of the offspring’s is a XX red-eyed mail with w and w+ alleles. The wild-card allele gave him the red eyes. Another offspring is a female that will die because its sex chromosomes are XXX with www+ alleles. Another offspring is a red-eyed male with a XO sex chromosome, and has a wild-card allele. There is also a white-eyed male offspring that is hemizygote with the sex chromosomes as XY, and a w allele. Another offspring is a white-eyed female with XXY sex chromosomes, and ww alleles. Lastly, there is a dead offspring because it has the YO chromosome. The reason it dies is because it needs one X chromosome to live, and the O means an absence of a chromosome.

Before she responds I just had to say this :D It gives me a moment of superority amongs the nerds :D


even though she actually pointed it out :)

[dna9488]

Before she responds I just had to say this :D It gives me a moment of superority amongs the nerds :D


even though she actually pointed it out :)

:rofl:

So she points out the mistake and you take the credit man. Thats sooo wrong


I actually am a nerd. Freshman year of college. I actually took my chem book (1000+ pgs) and started reading it during my cardio. I got the weirdest looks ever.

[magdalena]

With the Nullo-X allele, you can see it on the picture that the Drosophila produced eggs; there was a disjunction present and because of that one of the cells has two copies of genetic material and one doesn't have any. Nullo-X would mean then that the genetic material is absent in this cell.

Your explanation to the picture makes sense, just make sure you are clear from the start what you name XX or ww, it seems that sometimes you are switching back and forth and this may confuse the professor.
But yes, there are 6 possible outcomes, and they are just as you explained them.
And yes again for the YO genotype since the X is necessary to make an offspring since it carries most of the specialized structures (like nucleolus and mitochondrion).

The male with XO is a male because he is lacking another X chromosome which is necessary to make a female.
For the XY offspring I am not sure if it is hemizygote since it has both copies of genetic material. For it to be male it has to have XY, so I just don't see anything being wrong with it.


One more thing, on your quiz be specific and make sure you understand the difference between Homozygote, heterozygote and hemizygote.
Good luck to you and let me know if I can help you with anything else.