Prophase I marks the beginning of meiosis, where homologous chromosomes undergo synapsis and crossing-over to ensure genetic diversity. The phase is divided into leptotene, zygotene, pachytene, diplotene, and diakinesis, each playing a crucial role in the accurate segregation of chromosomes and the production of haploid gametes. This process is vital for evolution, as it introduces variation through independent assortment and recombination.
Show More
During prophase I, homologous chromosomes pair up and undergo genetic recombination through crossing-over, resulting in chiasmata that are crucial for proper chromosome alignment and segregation
Leptotene and Zygotene
The first two substages of prophase I, leptotene and zygotene, involve the formation of the synaptonemal complex and the pairing of homologous chromosomes
Pachytene and Diplotene
The next two substages, pachytene and diplotene, involve the completion of synapsis and the occurrence of crossing-over, leading to genetic diversity in the resulting gametes
Diakinesis and Metaphase I
The final two substages, diakinesis and metaphase I, involve further chromosomal condensation and the alignment of homologous chromosomes at the metaphase plate
During diakinesis and metaphase I, the nuclear envelope breaks down and the meiotic spindle forms, setting the stage for the separation of homologous chromosomes in anaphase I
Meiosis II involves the separation of sister chromatids, similar to the process of mitosis
Prophase II and Metaphase II
The first two phases of meiosis II involve the re-condensation of chromosomes and their alignment at the metaphase plate
Anaphase II and Telophase II
The final two phases of meiosis II involve the segregation of sister chromatids and the formation of four haploid daughter cells
Meiosis is crucial in generating genetic diversity through independent assortment of chromosomes and crossing-over, providing a vast potential for variation within a population
00
Phases of Prophase I in Meiosis
Leptotene, zygotene, pachytene, diplotene, diakinesis - stages with distinct chromosomal changes and functions.
01
Role of Synaptonemal Complex
Facilitates pairing of homologous chromosomes during synapsis, essential for recombination.
02
Outcome of Crossing-Over
Non-sister chromatids exchange genetic material, increasing genetic diversity in gametes.
