How does the genetic material differ between dizygotic twins and ordinary siblings? I am going to give a rough presentation on twin studies. The terms heritability and concordance are included already, but I struggle with understanding the difference of the genetic material of dizygotic twins and ordinary siblings. While ordinary siblings evolved from different sperm and egg cells, I only know that dizygotic twins form when two different sperm cells fertilize egg cells of the same cycle. However, I'm not sure if these cells are identical products of the same meiosis process. I appreciate your help and time.

Differences in genetic material between dizygotic twins and siblings are likely to be very similar.

> Dizygotic twins, or so-called fraternal twins, on the other hand, are no more genetically similar than any other set of siblings. - Utah.edu

Since all oocytes are all synthesized during fetal development, dizygotic twins are no more likely to come from a single mitotic division than siblings are.

Also note that in human females, only one egg comes from the a full mitotic division:

!meiosis