Pachytene

Pachytene is the third stage of the first prophase of meiosis, during which crossing over begins to form.

At the pachytene stage, homologous chromosomes come closer and closely associate with each other, forming bivalents. Synapsis occurs - close convergence of homologous chromosomes. At the points of contact, a synaptonemal complex is formed. At this time, recombination processes between homologous chromosomes begin - crossing over occurs, in which homologues exchange sections of chromatids.

Crossing over results in genetic diversity of gametes and is an important process during meiosis. Pachytene ends when homologous chromosomes separate and they begin to separate, moving on to the next stage of meiosis.

Pachytene is the third stage of the first prophase of meiosis. At this stage, conjugation of homologous chromosomes occurs and the process of crossing over (exchange of sections between homologous chromosomes) begins.

During pachytene, homologous chromosomes come together tightly along their entire length and form bivalents. Bivalents consist of two sister chromatids of each homologous chromosome. Chromosomes begin to contact in special areas called chiasmata.

During the formation of chiasmata, crossing over occurs - the exchange of sections between non-sister chromatids of homologous chromosomes. As a result of crossing over, each daughter cell ends up with a unique combination of genes from different parental chromosomes. This results in genetic diversity in the offspring.

Thus, pachytene is an important stage of meiosis, during which the genetic variability of future gametes is laid down.

Pachytene is the third stage of prophase I of meiosis. At this stage, the process of crossing over begins, which is an important step in meiosis. Crossing over is the process of exchange of genetic information between homologous chromosomes, which leads to the formation of new gene combinations and increased genetic diversity.

During prophase, several changes occur in chromosomes. First, the chromosomes become more compact and closely connected to each other. Second, the DNA within the chromosomes splits into two separate strands called sister chromatids. These chromatids are located next to each other and can exchange genetic information.

Crossing over occurs in the pachytene stage of prophase. At this point, sister chromatids begin to move relative to each other, which leads to the exchange of genetic information. This process can occur both within one chromosome and between different chromosomes.

It is important to note that crossing over is an important process in evolution, as it results in the emergence of new combinations of genetic traits in the offspring. This can help species adapt to changing environmental conditions and survive in more challenging environments.

Thus, pachytene is an important stage of prophase, which ensures the diversity of genetic combinations in the offspring and contributes to the evolution of species.

Pachytene is the third stage of prophase I of meiosis 2 division in the prointerphase human nucleus. In nuclear chromatin, chromosomes are counted and aligned, as well as the formation of areas with prostaglandin molecules at the periphery of the nucleus - this makes it possible to lyse the shell of the maternal nucleus near the cytoplasm located inside the maternal nucleus.

During pachytene, the length of the tubulin filament in chromosomes increases, which contributes to the formation of a new type of relationship between microtubules. Microtubules assemble the left chromosome diagonally and the right chromosome horizontally, forming a cross-shaped figure. They all line up longitudinally towards the equator. In this configuration, a pair of sex chromosomes, together with a pair of 4 of 5 autosomes, form an outer square called a chalyna, the remaining 5 of 6