Meiosis
Meiosis vs. mitosis
Male meiosis in the plant Allium triquetrum Stages of prophase I
leptotene
zygotene
pachytene
diplotene
From G.K. Rickards, The Cell Nucleus (1965)
diakinesis
Male meiosis in the plant Allium triquetrum
metaphase I
early anaphase I
anaphase I
From G.K. Rickards, The Cell Nucleus (1965)
Male meiosis in the plant Allium triquetrum anaphase I
telophase I
metaphase II - anaphase II anaphase II
(early)
interkinesis
anaphase II
prophase II
telophase II
(late)
From G.K. Rickards, The Cell Nucleus (1965)
metaphase II
daughter cells
Prophase I in mouse fetal ovary
Leptotene
Giemsa staining for chromatin
silver staining for synaptonemal complex
From R.M. Speed (1982)
Prophase I in mouse fetal ovary
Zygotene
Giemsa staining for chromatin
silver staining for synaptonemal complex
From R.M. Speed (1982)
Prophase I in mouse fetal ovary
Pachytene
Giemsa staining for chromatin
silver staining for synaptonemal complex
From R.M. Speed (1982)
Prophase I in mouse fetal ovary
Diplotene
Giemsa staining for chromatin
silver staining for synaptonemal complex
From R.M. Speed (1982)
Development of the synaptonemal complex
From Alberts et al., Molecular Biology of the Cell
Recombination nodules in pachytene
Schematic drawing (Alberts et al., 1994)
From tomato chromosomes – EM photo (www.mgel.msstate.edu/chromosomes.htm)
Synaptonemal complex in a mouse spermatocyte (pachytene or late zygotene)
Role of chiasmata in metaphase I and anaphase I Photos: G. K. Richards
metaphase I
anaphase I
Drawing: Alberts et al., Molecular Biology of the Cell
Oogenesis
In the diplotene of female meiosis, many animals form lampbrush chromosomes
Part of a lampbrush chromosome in amphibian oocyte (from S. Gilbert, Developmental Biology)
Mature frog egg
Photo: Kinexus Bioinformatics Corporation
Mature infertilized mammalian oocyte
Cortical granule in sea urchin egg
(from S. Gilbert, Developmental Biology)
Spermatogenesis
Syncytium of spermatogenic cells
(from S. Gilbert, Developmental Biology)
Human spermiogenesis
(based on S. Gilbert, Developmental Biology)
Detergent-treated mouse sperm cell