At the end of mitosis, one cell has divided into two diploid cells. But at the end of meiosis I, there are two haploid cells. How are the two processes different to produce these two types of cells?
2 Answers
At the start, all the cells are 2n, diploid cells. By far the largest difference between meiosis I and mitosis is that mitosis results in genetically identical, diploid somatic cells. Meiosis, in it's entirety, results in gametes of haploid genetic information, but the genetic information is not identical due to crossing-over events that happened during meiosis I.
What you should also note from the figure: Each chromatid represents 1 DNA molecule. In mitosis, the cell will begin with 4 chromosomes and 8 chromatids. After cytokinesis, the somatic cell will have 4 chromatids and 4 chromosomes. This propagates during the next round of mitosis. In meiosis: The cell starts with 8 chromatids and 4 chromosomes. After meiosis I each cell has 4 chromatids and 2 chromosomes. After meiosis II, each cell has 2 chromatids and 2 chromosomes. You're halving the amount of genetic material each round of meiosis, and this can't be propagated indefinitely.
Source: Tortora, GJ (2008). Principles of Anatomy and Physiology. 12th ED.
-
1
-
$\begingroup$ @Ana Wiley library system, source link. It's Tortora "Principles of Anatomy and Physiology," 12th ed. $\endgroup$– CKMSep 14, 2017 at 18:47
the difference with easy way that the arrangement of chromosome on equatorial plate in metaphase 1- in mitosis all chromosome arrange on equatorial line randomly and single so when it separate in anaphase separate to chromatide ( all chromatides), and each cell have 2n however 2- in meiosis 1 chromosome arrange in duple or couples so when it separate as one chromosome , and each cell have n only i hope it is useful for u
-
2