Biology question (1 Viewer)

zizi2003_

Well-Known Member
Joined
Dec 18, 2020
Messages
1,471
Gender
Female
HSC
2021
Basically,
The model that we have now recognises that DNA replication (interphase) occurs before crossing over (prophase I), as a result of there are two homologous pairs of chromosomes
Also, it is now known that crossing over occurs between the two chromatids in the tetrad. This means that there are parental chromosomes (see the ones that are completely black/white, with no recombinant DNA?) that do not undergo the process of crossing over.Screen Shot 2021-08-07 at 10.39.20 pm.png
The effect of this is that not all gametes produced will contain chromatids that have undergone crossing over
 

[Blank]

[Blank]
Joined
Aug 7, 2021
Messages
1,695
Location
Sydney
Gender
Male
HSC
2021
Uni Grad
2023
Ok, how about this answer:
The chromosomes exchange information through 'crossing over', however, the diagram shows that it was performed from the chromatid, and SOMEHOW exchanged the specifically needed alleles to express the phenotype. This means, when comparing their diagram to our current one, ours is more in-depth in regards to the exact assessment of how crossing over occurs on any part of the chromosome that is genotypically mirrored to the 2nd chromosome of the same type.
 

[Blank]

[Blank]
Joined
Aug 7, 2021
Messages
1,695
Location
Sydney
Gender
Male
HSC
2021
Uni Grad
2023
Basically,
The model that we have now recognises that DNA replication (interphase) occurs before crossing over (prophase I), as a result of there are two homologous pairs of chromosomes
Also, it is now known that crossing over occurs between the two chromatids in the tetrad. This means that there are parental chromosomes (see the ones that are completely black/white, with no recombinant DNA?) that do not undergo the process of crossing over.View attachment 31452
The effect of this is that not all gametes produced will contain chromatids that have undergone crossing over
MY GOSH! I WAS SO CLOSE! I was talking about that a bit at the end of my reply!
 

zizi2003_

Well-Known Member
Joined
Dec 18, 2020
Messages
1,471
Gender
Female
HSC
2021
Ok, how about this answer:
The chromosomes exchange information through 'crossing over', however, the diagram shows that it was performed from the chromatid, and SOMEHOW exchanged the specifically needed alleles to express the phenotype. This means, when comparing their diagram to our current one, ours is more in-depth in regards to the exact assessment of how crossing over occurs on any part of the chromosome that is genotypically mirrored to the 2nd chromosome of the same type.
wait what do you mean by 'genotypically mirrored to the 2nd chromosome of the same type'?
Do you mean 'homologous chromosomes' - this term would be better to use as they are chromosomes of the same size and with the same loci, but differing alleles
 

[Blank]

[Blank]
Joined
Aug 7, 2021
Messages
1,695
Location
Sydney
Gender
Male
HSC
2021
Uni Grad
2023
wait what do you mean by 'genotypically mirrored to the 2nd chromosome of the same type'?
Do you mean 'homologous chromosomes' - this term would be better to use as they are chromosomes of the same size and with the same loci, but differing alleles
Yeah, you're right - my mind went blank when thinking about the differences between the two parents, but regardless, they are both the same chromosome type.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top