VCE Biology Question Thread

[Bruzzix]

Yeah I would have said B. A is technically right since a bottleneck is a type of genetic drift

Why would you have said B?

[heids]

Why would you have said B?

Because bottleneck = a sudden drop in the population (due to a disaster) so that you'll suddenly have a really small population, thus all descendants will be from just a few.

[Sine]

So this is what the study design says for biotechnology

DNA tools and techniques: gel electrophoresis; DNA amplification; DNA sequencing; making a
recombinant plasmid; bacterial transformations; DNA profiling; gene cloning; and using plasmids
as gene delivery systems

I'm unsure of what we need to know about bacterial transformation; do we need to know that it can occur or do we need to know the details of the process such as electroporation and heat shock therapy.
Also "using plasmids as gene delivery systems" does that mean only plasmids not other stuff like bacteriophages.
Short tandem repeats and hyper variable regions what point of the study design is this in and what are we required to know about these.
I know that STR locus is a sequence of base repeats and it can be used to identify someone uniquely and hypervariable regions is the d-loop of mtDNA.

EDIT: released the STR's and other stuff is under DNA profiling which is quite vague.

[Bruzzix]

Because bottleneck = a sudden drop in the population (due to a disaster) so that you'll suddenly have a really small population, thus all descendants will be from just a few.

But no where in the question did it say there was a sudden drop in the population. Also when we diverged, we would have started with a relatively small population, right?

[jyodesh.com]

But no where in the question did it say there was a sudden drop in the population. Also when we diverged, we would have started with a relatively small population, right?

The question said that all Europeans are descendants of 200 individuals so its implying that this is an example of the Founder effect. The Founder effect is when a small group of individuals become reproductively isolated from the larger population thus separating a limited portion of the gene pool in the isolated individuals. For this reason, the Founder effect is a type of bottleneck event. Bottleneck is not the same as genetic drift (im not sure if bottleneck is a type of genetic drift or if its completely different). Genetic drift describes the random fluctuations in allele frequency that occurs as a result of random mating thus can result non-adaptive mutations e.g. loss in the ability to synthesise vitamin C in primates. Genetic drift occurs in all populations no matter how large, however the random fluctuations due to random mating are more pronounced in small populations thus more likely to result in the loss of alleles. A random reduction in the size of a population is known as the bottleneck effect. Since bottleneck results in the random reduction of individuals in a population, bottlenecked populations are more susceptible to genetic drift.
Hope this helps

[Biology24123]

The question said that all Europeans are descendants of 200 individuals so its implying that this is an example of the Founder effect. The Founder effect is when a small group of individuals become reproductively isolated from the larger population thus separating a limited portion of the gene pool in the isolated individuals. For this reason, the Founder effect is a type of bottleneck event. Bottleneck is not the same as genetic drift (im not sure if bottleneck is a type of genetic drift or if its completely different). Genetic drift describes the random fluctuations in allele frequency that occurs as a result of random mating thus can result non-adaptive mutations e.g. loss in the ability to synthesise vitamin C in primates. Genetic drift occurs in all populations no matter how large, however the random fluctuations due to random mating are more pronounced in small populations thus more likely to result in the loss of alleles. A random reduction in the size of a population is known as the bottleneck effect. Since bottleneck results in the random reduction of individuals in a population, bottlenecked populations are more susceptible to genetic drift.
Hope this helps

Sorry no, genetic bottleneck and founder effect are a type of genetic drift.

[thettywetty]

As substitution mutations occur at a greater rate in mtDNA than in nuclear DNA, how is that useful in establishing evolutionary relationships between species?

[Bruzzix]

How do scientists classify species of similar but extinct animals when they can't test to see if they can produce fertile offspring?

[cosine]

Can someone help out on this one please?

Please :3

[Maca 13]

As substitution mutations occur at a greater rate than nuclear DNA, how is that useful in establishing evolutionary relationships between species?

Are you talking about mtDNA when you say substitution mutations? Because mtDNA has a higher frequency of mutations than DNA, this feature can help us figure out when two species diverged, based on the number of mutations. The more mutations one species has when compared to another, the longer it has been since the two species diverged.
I'm not sure if this was what you were asking (I hope this helped)? 

[Bruzzix]

Are you talking about mtDNA when you say substitution mutations? Because mtDNA has a higher frequency of mutations than DNA, this feature can help us figure out when two species diverged, based on the number of mutations. The more mutations one species has when compared to another, the longer it has been since the two species diverged.
I'm not sure if this was what you were asking (I hope this helped)? 

This is off topic but holy shit man! You're doing SEVEN subjects in one year and one of them is a UNI extension and another is a language! HOW DO YOU COPE!?

[thettywetty]

Are you talking about mtDNA when you say substitution mutations? Because mtDNA has a higher frequency of mutations than DNA, this feature can help us figure out when two species diverged, based on the number of mutations. The more mutations one species has when compared to another, the longer it has been since the two species diverged.
I'm not sure if this was what you were asking (I hope this helped)? 

Yes! I edited my post thanks.
Thanks Maca!

[thettywetty]

I have another question..

Regarding the theories of how homo sapiens arised, in the Out of Africa hypothesis (homo sapiens arised in Africa and then migrated to other countries), the evidence is that the mtDNA shows that there is greater variation in the African population.

I don't understand the correlation 

Someone send help please

[Maca 13]

I have another question..

Regarding the theories of how homo sapiens arised, in the Out of Africa hypothesis (homo sapiens arised in Africa and then migrated to other countries), the evidence is that the mtDNA shows that there is greater variation in the African population.

I don't understand the correlation 

Someone send help please

I think that this means that because there were more mutations in the mtDNA in the African population, then there was possibly a diverge in that population. One of the species that resulted from this divergent evolution may have eventually resulted in modern humans, which we can then trace back to one woman through mtDNA mutations?    Someone please correct me if I'm wrong...

[BakedDwarf]

As substitution mutations occur at a greater rate in mtDNA than in nuclear DNA, how is that useful in establishing evolutionary relationships between species?

mtDNA sequencing is able to trace divergences over a relatively short time to a greater degree than nuclear DNA