How do I identify the different stages of meiosis under microscope?

Question

This is a question I'm troubled with as my exams are knocking at the door. I need help so I decided to post this here.

Here's what I know and understand about meiotic stages:

Specimen: Grasshopper (Gesonula punctifrons) testis whose 2n= 23

Note: The character in bold and italics is the identifying feature of the concerned stage.

Prophase:

Leptotene

• The uncondensed chromosomes are visible as a cloud of thin threads.
• Each chromosome consist of two chromatids which are not visible.
• The single darkly stained X chromosome is found at the periphery of the nucleus.
• Late in this stage the chromosomes attach themselves by telomeres to the inner membrane of the nuclear envelope forming a bouquet.
• Nuceolus and nuclear membrane are present.(not visible under compound microscope)

Zygotene

• The uncondensed chromosomes are visible as a cloud of threads.
• Homologous chromosomes undergo synapsis forming bivalent.
• The single darkly stained X chromosome is present slightly off the periphery of the nucleus.
• Nucleolus and nuclear membrane are present.(not visible)

Pachytene

• The chromosomes show some degree of condensation.
• The sister chromatids separate to form tetrad a structure with four chromatids.
• Crossing over between non sister chromatids of homologous chromosomes occur leading to formation of X shaped chiasmata.
• Nucleolus and nuclear membrane are present.(not visible)

Diplotene

• The chromosomes are thick and darkly stained.
• The chromosomes are wooly in appearance.
• The paired chromosomes separate from each other except for the chiasmata.
• Nucleolus and nuclear membrane begin to diappear.(can't be detected)

Diakinesis

• The chromosomes are thick and darkly stained.
• Terminalisation of chiasmata initiates.
• The bivalents appear rod, diamond or oval shaped.
• The nucleus and nuclear membrane disappear completely.

Metaphase-I

• The chromosomes are thick and darkly stained.
• Presence of twelve chromosomal elements (11 tetrad + X chromosome).
• The chromosomes are aligned at the equitorial plate.
• Terminalisation of chiasmata completes.

Anaphase-I

• Two groups of chromosome are in the act of separation.
• One group is with 11 autosomes and the other group with 11 autosomes and a X chromosome.
• The chromosomes are T or V shaped.
• Each chromosome is in dyad state.
• The centromere is undivided.

Metaphase-II

• There is 11-12 dyads present.
• The chromosomes are thick and darkly stained.
• The dyads are arranged in circle or flower like fashion.
• The chromosomes are rod like

Anaphase-II

• The sister chromatids of a dyad separate due to splitting of centromere.
• Two groups of chromosome are in the act of separation.
• One group is with 11 autosomes and the other group with 11 autosomes and a X chromosome.
• The chromosomes are rod like

Here's an image which has nearly all the stages except telophase.Can someone label the stages?

Here's what I feel about them:

Finally am I correct? How do I identify them correctly? Could you site some authentic references?

Answer 1

ID characteristics that can help you recognize diplotene better:

diplotene : the only difference between this phase and Diakinesis is that The centrosomes reach the poles.

you can see the photos of diplotene and diakinesis here :

http://www1.biologie.uni-hamburg.de/b-online/e09/meiosea.htm

(a) polyploid nutri-tive cells with many heteropicnotic chromatin bodies; (b) leptotene-zygotene; (c) pachytene; (d) diffuse stage; (e) di-plotene; (f) diakinesis; (g) metaphase I; (h, i) anaphase I; (j) telophase I;. (k) metaphase II; (l) anaphase II; (m) telophase II; (n) round spermatids; (o) elongating spermatids; (p) head of sper-matozoas. Big arrows indicate sex chromosomes, small arrows point to nucleoli and arrowheads indicate m-chromosomes

You can see all the phases clear and perfectly separated here :

http://biology.about.com/od/meiosis/ss/meiosisstep.htm#step1

by the way , try to adjust microscope as best as you can & don't put much oil immersion .