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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?

Image 1

Here's what I feel about them: Image 2

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

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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

diplotene Diakinesis

 (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

(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 .

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

  • $\begingroup$ long answer for this Question ?! there is no other thing to explain . Sanjukta Ghosh asks how to identify different phases of meiosis under microscope and I provided a link that show all 10 phases perfectly clear . I could upload every single photo by my self on the answer if you are asking for it . why should I put some additional content and confuse the questioner ? $\endgroup$ – BlueFoxy Aug 31 '16 at 17:44
  • $\begingroup$ The images you have linked are not light microscopic views. They are far too clear for light microscope. Besides it lacks the substages of prophase I. I was also looking for an answer that specifies the key identifying characters. It will be helpful if you could improve the answer. Moreover I have attached an unedited image of meiotic stages. Could you label the stages there and explain how you are identifying them. $\endgroup$ – Tyto alba Aug 31 '16 at 18:57
  • $\begingroup$ They are light microscopic view of course the background is white for better contrast they've been coloring very good and adjust very well . that's how it's gonna be in the exams as far as I've seen . but don worry I will improve the answer by specifying the key id characters . but you should know it's a tricky skill some times no one can say what the phase is as it is really unclear ... these cases are not gonna be on the exams or so . $\endgroup$ – BlueFoxy Aug 31 '16 at 19:52

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