It's over!

[brian77]

Hey guys, this question might've been answered previously, but since this forum is already 38pgs and increasing, I really cbs looking back. So, here it is: I can't quite get my head around how that bird-reptile fossil got trapped in that 'slab of stone'. The 'slab of stone' part really gave me headaches.

[simpak]

I think the issue despite whether it's possible or not to date it is whether this actually helps in proving the hypothesis. My knowledge of all this stuff is pretty much non-existent now, but I don't see how dating it can reliably help. Plus, I vaguely recall from a textbook that they've shown that the majority of the mtDNA in present day people can be traced back to I think it was 3 Africans. So yeh, D? (And no, I am not authoritative on evolution at all.)

is theres variation if mtdna doesnt that mean that its supports Multiregional, because for it to SUPPORT out of africa there should be little variation in mtDNA cos theyve all come from the same area
because these are of worldwide sites, variation would indicate different groups of fossil populations ie Multiregional thereby disproving Out of Africa

by looking at decompostion, if fossils in regions outside of africa are less decomposed than fossils in africa, this would indicate original populations in africa and later around the world ie supporting Out of Africa theory

i dont think U-235 dating can be used for 100,000 years bc its half life is 700 million or something like that ruling A out i think

No, because you compare the mtDNA to the Africans currently living in the region to give you an idea of the theories.
That's how they deduced that Out-of-Africa was the better one in the first place, p. sure.
Simply looking at the decomposition isn't good enough, imo, because the fossilization conditions in one area might be better than that in another and so more decomposition might have occurred in different areas.

[cochra]

Normally, yes, the well would have a fluorescent tag to bond to dsDNA and therefore you would only get green in that well. in this case however, they had each strand of DNA being run through the micro-array labelled:
"Solution 1:  Complementary normal strand, labelled with fluorescent, green dye.
Solution 2: Complementary strand from DNAof person with breast cancer, labelled with red, fluorescent dye."

So in this case, if she was heterozygous, she would have had a green tinged with red result...
also, didn't you mention earlier that this particular gene has a mainly recessive effect? I realise that this is not on the curriculum, but surely the examiners would know this?

[fdsfsgdfgdf]

But that the mother had breast cancer doesn't show whether she had inherited the mutation from her parents or a somatic mutation. Somewhere earlier in the thread someone (may have been me, thinking about it) said something about how the mother was probably homozygous for this mutation, as the microarray only showed one red band, and the green band was pure green, and not green tinged with red, which it would have been if the mother's DNA had bound there too... Wouldn't this mean that the daughter would get the allele, and therefore show up red?

How could it be tinged with red? The green well only has green dye in it. I think you're misunderstanding how DNA chips work. She's definitely heterozygous.

what if she is hetro wouldnt it show red in two wells?

[shinny]

Normally, yes, the well would have a fluorescent tag to bond to dsDNA and therefore you would only get green in that well. in this case however, they had each strand of DNA being run through the micro-array labelled:
"Solution 1:  Complementary normal strand, labelled with fluorescent, green dye.
Solution 2: Complementary strand from DNAof person with breast cancer, labelled with red, fluorescent dye."

So in this case, if she was heterozygous, she would have had a green tinged with red result...
also, didn't you mention earlier that this particular gene has a mainly recessive effect? I realise that this is not on the curriculum, but surely the examiners would know this?

Oh, ok this makes a lot more sense. Yep, you're correct, sorry. Misunderstood their method by confusing it with another DNA chip method I learnt. In that case, she's homozygous. Still doesn't sort out whether it was a somatic or germline mutation though.

[shinny]

And in actual fact, what is the last question even specifically asking for then? Am I just getting a complete mental blank here or is the question a bit ambiguous as to what it's actually asking for... I mean, as someone else said, since the person being tested has red dye, then she'd be..uh, red?

And yes, sorry for my misunderstanding from up to this point regarding this question.

[simpak]

A daughter of Patient X was also tested for the first segment of the allele.
Would you expect her result to be red, green or black?  Explain your answer.

[cochra]

I read it as that method the first time through to . Much more commonly used i think.

I presumed it was inherited, because the chances of her having exactly the same substitution on both chromosomes are pretty low...however, there isn't actually anything to really show either way.

I thought she would be red, as if it was a hereditary mutation and the mother was homozygous, she would have inherited it. The excess DNA was washed of the plate, so the red dye would only be shown where the DNA had hybridised.

[shinny]

A daughter of Patient X was also tested for the first segment of the allele.
Would you expect her result to be red, green or black?  Explain your answer.

I didn't mean literally =P I've got the question, but I don't get what it's asking for. Her 'result' in regards to which well? The well with the normal complementary DNA? The well with the mutated complementary DNA? Or is it as simple as what someone else stated above; that her test will be red because the person being tested has red dye.

[shinny]

I read it as that method the first time through to . Much more commonly used i think.

I presumed it was inherited, because the chances of her having exactly the same substitution on both chromosomes are pretty low...however, there isn't actually anything to really show either way.

I thought she would be red, as if it was a hereditary mutation and the mother was homozygous, she would have inherited it. The excess DNA was washed of the plate, so the red dye would only be shown where the DNA had hybridised.

But the point is, the daughter's DNA would have had to hybridise SOMEWHERE, whether it was on the normal or mutated well. Hence, red will show up either way given that they didn't specify whether a specific well would be green or red.

[qshyrn]

sorry to interrupt ur discussion on that question, but shinny , what do u think of MC no. 14?

[shinny]

sorry to interrupt ur discussion on that question, but shinny , what do u think of MC no. 14?

Don't ask me about evolution, I have no idea =P

[fdsfsgdfgdf]

smiley you doing solution ?

[shinny]

Nah, I can't do half the exam given I can't remember anything about evolution. Also, I've got an exam on Thursday. I'll just go over anything that's contentious. You guys sort it out amongst yourselves =T

[fdsfsgdfgdf]

i put A :S i has to be A because it says put population together increase genetic variation and variation leads to better chance to survive extinction