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Questions tagged [crossover]

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0answers
19 views

Is the holiday model an anomaly in terms of the general genetic principle?

In terms of the holiday model, the chromosomes can form a cruciform structure. When nicked vertically, both arms of the chromosomes contain crossover DNA (see part f of diagram). However, it is ...
4
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3answers
93 views

Can chromosomal crossover undo itself?

If I have alleles AB on one chromosome and ab on another, and if A and B are far from each other (and also a and b), then there is a lot of chromosomal crossovers happening. If I crossover 7 times, ...
2
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1answer
980 views

Why does chromosome inversion happen?

I read that chromosome inversion is a type of genetic mutation. Why does inversion happen? What is the purpose? I also read that if genes do not match up during cross over between inverted ...
1
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1answer
261 views

Does crossover happen between chromosomes from grandparents?

Rephrasing question: does crossover happen after sperm and egg meet each other, but before formed fetus starts to grow? As I understand sperm and egg of human are haploid cells. That means this cells ...
3
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1answer
568 views

Why does crossing over take place at all?

I already know that crossing over causes genetic variation. My question is that since DNA is a stable molecule, why would it undergo process like crossing over during which it becomes so unstable and ...
0
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2answers
631 views

Does chromosome cross occur over male and female or vice versa? [closed]

My understanding is homologous chromosome pair, which means male and female chromosome inside the DNA. So if that's homologous how does male do with female? Does it flip over and change direction, ...
0
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1answer
69 views

A diagram of a crossover [closed]

How can one draw a crossover between ABK and aBk where genes A and B follow the Mendel's law of independent assortment and gene K does not i.e. K is linked to B?
0
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1answer
534 views

When do 3 germ layers form in embryo? And why is there only one mature egg formed?

During the process of pregnancy, when do the 3 germ layers form in embryo? Is it after formation of gastrula? Also, during oogenesis, why does only one mature egg form? Why don't use polar body egg ...
0
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0answers
27 views

Why only human have noticeable difference in face? [duplicate]

Our facial appearance is pretty much different from each other unless we are talking about twin. Credit goes to crossing over of chromosome. But why can't we distinguish between other animals of same ...
1
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1answer
539 views

Why does allele linkage cause disproportionate phenotypic ratios? [closed]

I was learning about allele linkage in Biology class and I got confused by the resultant phenotypic ratios. Say you have a dihybrid cross BbGg x BbGg. The Punnett square would look like the ...
12
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4answers
495 views

How does the molecular machinery choose where to cut a chromosome for recombination?

I'm wondering about a few technicalities of crossover in meiosis. The point of crossover is to create new chromosomes that don't have the same allele combinations as the original two chromosomes. ...