Does Independent Assortment Occur during Prophase I or Metaphase I?

[amaghsou]

Kind of confused since every sources says something else. Does law of Independent Assortment occur during Prophase I or Metaphase I?

My thinking is that it happens in Prophase I as the rest of crossing over is happening but sources say that the Law of IA happens during Metaphase I. Someone please clear this up before I go crazy.

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[FeralisExtremum]

I would say Anaphase I is most relevant. The law of independent assortment states that the orientation and subsequent separation of each homologous chromosome pair during meiosis is completely independent relative to the separation of the other pairs.

But the Law of Independent Assortment is more of a general concept than a description of a specific sequence of events. More specifically: it says that the way one pair of homologous chromosomes separates is completely independent of how each of the others will separate (e.g. if your first chromosome pair separated so that your mom's chromosome went to the left and your dad's to the right, this doesn't change how the second chromosome pair will separate - your mom's could go to the right or the left, each separation is considered its own separate isolated event).

This is basically just an explanation for why gametes end up with different combinations of alleles.

 

[I-hate-alginate]

Lol I thought it would happen in anaphase I because that's when the chromosomes separate.

 

[amaghsou]

I would say Anaphase I is most relevant. The law of independent assortment states that the orientation and subsequent separation of each homologous chromosome pair during meiosis is completely independent relative to the separation of the other pairs.

But the Law of Independent Assortment is more of a general concept than a description of a specific sequence of events. More specifically: it says that the way one pair of homologous chromosomes separates is completely independent of how each of the others will separate (e.g. if your first chromosome pair separated so that your mom's chromosome went to the left and your dad's to the right, this doesn't change how the second chromosome pair will separate - your mom's could go to the right or the left, each separation is considered its own separate isolated event).

This is basically just an explanation for why gametes end up with different combinations of alleles.

ahh great explanation! Makes total sense. It is totally irrelevant to crossing over I see.

 

[Master Yoda]

Kind of confused since every sources says something else. Does law of Independent Assortment occur during Prophase I or Metaphase I?

My thinking is that it happens in Prophase I as the rest of crossing over is happening but sources say that the Law of IA happens during Metaphase I. Someone please clear this up before I go crazy.

ADA suggests to review biology concepts in Campbell Biology 9th edition....
Chapter 13 pages 257-259 explain your question in detail.