Question

What is Leptotene stage?

Answer 1

Hint: This stage is also referred to as the bouquet stage because of the specific arrangement of chromosomes in the nucleus. Chromosomes link to one portion of the nucleus towards the centrosome.

Complete Answer:
- Meiosis is structure of cell division that produces genetically diverse sex cells or gametes. It comprises two successive nuclear divisions namely meiosis I and meiosis II.
- Meiosis I consists of four stages: prophase I, metaphase I, anaphase I, and telophase I. Prophase I is the first stage and consists of the 5 sub-stages, they are- leptotene, zygotene, pachytene, diplotene and diakinesis.
- Leptotene is the first substage and it is when the replicated chromosomes start to condense into long strands inside the nucleus.
- The chromosomes at this stage are threadlike. And in every chromosome, chromomeres (i.e. serially aligned beads or granules resulting from nearby coiling of a constant DNA thread) can be visible.
- The sister chromatids that make up the chromosome are so closely linked together at this end. Because of this, the sister chromatids seem to be a single strand since they are visually unrecognizable from each other.

Note: At the leptotene phase the chromosomes seem as long, fine threads. Duplication of centriole takes place and they pass to opposite ends of the nucleus, where they undergo further duplication. Leptotene is accompanied through the zygotene level (stage).