Does phenotype expression lessen?

[GDG]

Hey I was wondering after listening to my teacher who has already made like 2 errors in her lectures. [I am in grade 12 high school]. I have never heard of this but she said that as DNA replication occurs within the generations of cells a gene expression, lets say for example the height of a person. As DNA replication keeps occuring that gene expression or phenotype will decrease, so in other words the persons height will begin to decease and among the family members that live after him!

Is this true or no? Thanks for the answer!

[Eternal-Cowboy]

Why are you learning 9th grade material in 12th grade?

[Chathurga]

Definatly not.

[PopeOfDope]

I'm not too sure about height, but there are some genetic diseases which increase expression from generation to generation. http://en.wikipedia.org/wiki/Anticip...%28genetics%29

Basically because of the nature of the sequence of bases, its very easy to make a mistake and the more you replicate, the more mistakes get made. These mistakes are then passed on to the next generation where it gets more mistakes etc. This could lead to the increased expression of a disease or maybe decrease the expression of a normal gene (I have no examples of it and I don't know if it exists)

I had a lecture on this 2 weeks ago :)

[GDG]

I'm not too sure about height, but there are some genetic diseases which increase expression from generation to generation. http://en.wikipedia.org/wiki/Anticip...%28genetics%29

Basically because of the nature of the sequence of bases, its very easy to make a mistake and the more you replicate, the more mistakes get made. These mistakes are then passed on to the next generation where it gets more mistakes etc. This could lead to the increased expression of a disease or maybe decrease the expression of a normal gene (I have no examples of it and I don't know if it exists)

I had a lecture on this 2 weeks ago :)

Ah that was the idea I had that mistakes could be made through replication which could cause such changes. I guess the height example maybe a good example, because every new generation of people does does shrink by some millimetres, thus we could presume it is due to the genetic replication where mistakes are made. Although then how exactly is it that minor changes occur? I mean if we look at sickle cell anemia, one change from glutamic acid to valine causes it all. So this is a serious disease yet something like height is not that big of a change if we compare ourselves to our children. Like what I want to say or ask is, do different mutations act in different levels of mutation or change?
-= Double Post =-

Why are you learning 9th grade material in 12th grade?

Um I don't know if you took grade 11 or grade 12 Biology classes, but basically they expand on the molecular biology part of grade 9. Like in grade 9 you learn the simple stuff but in grade 12 you learn how everything works at the molecular level, so atomt to atom. Also how genetic diseases are formed and what happens to proteins and all. It is quite interesting! I love it can't wait to study molecular biology next year in university!

I had a lecture on this 2 weeks ago

I'm presuming you study molecular biology or just biology at university? Or maybe high school but w/e! Just wanted to know if you do and if so what do you think of it so far and what do you find most interesting?

[LampShade]

I guess the height example maybe a good example, because every new generation of people does does shrink by some millimetres, thus we could presume it is due to the genetic replication where mistakes are made.

No, height is a very ****ty example. Every new generation does not shrink, its the other way around. Mistakes that are caused through replication would not cause height changes unless it is when you are just a bunch of cell or the mistake happens to your thyroid(I think thats it...could be wrong)

Although then how exactly is it that minor changes occur? I mean if we look at sickle cell anemia, one change from glutamic acid to valine causes it all.

If you are taking biology you should know; deletion, replacement, and addition. The DNA/RNA is code/instructions, and if you read some instructions wrong you may get a nasty result or wind up with a small change or none, hopefully beneficial.

Like what I want to say or ask is, do different mutations act in different levels of mutation or change?

There are no 'levels' of mutation and change, just consequences which can vary. One kind of well know mutation is cancer, and viruses can be made by mutations(They have to be big mutations).

[SpiderJames]

all I kno is that my dad got the bald gene, and now it will go onto my kids hehe, Im gonna laugh at them so hard when they realize they are gonna be bald

[PopeOfDope]

No, height is a very ****ty example. Every new generation does not shrink, its the other way around. Mistakes that are caused through replication would not cause height changes unless it is when you are just a bunch of cell or the mistake happens to your thyroid(I think thats it...could be wrong)

Height was a crappy example and humans are getting taller, you are right. Replication mistakes CAN cause increase in height such as Kleinfelter syndrome and some forms of gigantism but they are rare. The thryoid does contribute to height, but the dominant contributor is your piruitary and hypothalamus, which release growth hormone.

If you are taking biology you should know; deletion, replacement, and addition. The DNA/RNA is code/instructions, and if you read some instructions wrong you may get a nasty result or wind up with a small change or none, hopefully beneficial.

True..also chromosome number can also mess things up e.g. downs syndrome

There are no 'levels' of mutation and change, just consequences which can vary. One kind of well know mutation is cancer, and viruses can be made by mutations(They have to be big mutations).

There are levels of mutation for some types of mutation e.g. the more deletions you have, the worse the disease. A good example is the number of mutations on the distrophin gene relates to how bad the Duchennes Muscular Dystrophy is.

[GDG]

:) I know all about deletion, replacement, and addition and how they are very prone to happening during the replication processes such as mitosis and specially meiosis where recombination between sister chromatids occur. But the whole point I wanted to make in this thread was to see if humans are getting shorter, cause that is the example that my teacher used.

I have a quick question, I never really got the whole picture of radiation and cancer. It maybe that they don't go into the molecular level of mutation build up during grade 12, which is why I can't wait to start university. But I was wondering how exactly is radiation a cause of cancer or other mutations? What happens at the molecular level to the DNA structure or the nucleotides (or genes)? Like is it the excess heat of the electromagnetic waves that cause the DNA structure to break up at parts and thus it obtains sometimes an extra amount of nucleotides disrupting the genetic code or is it something else? Thanks for the answer.

[Jatt101]

By radiation...they entirely mean UV light. UV light is special in way because it can break organic bonds and also change conformation of organic molcules (ie parts of nucleotides). You won't understand what actually occurs on the molecular level until you take a non-freshman biology class relating to it...until than don't worry about it. Are you in AP biology right now?

[GDG]

If you mean applied Biology when you say AP Biology then no. I actually take an academic Biology course, since I plan on entering university and they require academic courses!

[Sylar]

from what know if talking about humans height, eye color,and hair color are traits to never focus on you you would have to focus on purely hereditary traits such as cleft chin widows peak and cheek bones

[Darth Budd]

I'm not too sure about height, but there are some genetic diseases which increase expression from generation to generation.

ZOMG INBREEDING!!!

[mannymix03]

k honestly, you can't black and white things like this, its a complex process and you can't really cite specific examples that apply to the whole field.

[Evera]

No.

I want to kick your teacher in the face.