With the help of suitable diagram explain the five stages of prophase -1 of moiesis
Answers
Hello there!
To summarize, the five stages of prophase 1 in meiosis are leptonema, zygonema, pachynema, diplonema, and diakinesis.
These stages are categorized based on the presence of a key structure.
In leptonema/leptotene stage, the chromatins are starting to coil and you can actually see the chromatin-histone structures or chromomeres. During this stage, the chromosomes undergo rough homology search to find their homologous pairs.
In zygonema/zygotene stage, the chromosomes are more coiled forming bivalents. During this time, the chromosomes have already formed their pairs however, the sister chromatid of each homologous chromosome is not yet observable.
In pachynema/pachytene stage, a tetrad is now observable for each chromosomal pair. A tetrad is composed of 2 pairs of sister chromatids from each homologous chromosome.
In diplonema/diplotene stage, a chiasma is observed. This chiasma is where crossing over or exhange of genetic material has occured. This means that crossing over occurs between pachytene and diplotene stage and the resulting structure is the chiasma.
Lastly, in diakinesis, terminalization occurs. Terminalization is where the point of connection between two non-sister chromatids are moving to the tip-most of the chromosome or near the telomeres.
Image source: Klug et al. 2012. Concepts of Genetics. Pearson Education, Inc.
I hope this will help you!
