What is chromatid? Formation of chromatids

What is chromatid? Cell division is important for the life of a multicellular organism. In the end, we were all created from a single cell that shared over and over again. During this process, the nucleus also undergoes certain transformations in eukaryotic cells, which are called mitosis and meiosis. Chromatids are copies of chromosomes that were created before nuclear fission.

Variability within a species

When it comes to evolution, genetic diversity deserves special attention. In meiosis (the process of nuclear fission), a cell is formed from the haploid gamete spermatozoon and the egg. Genetic diversity is increasing in two main directions. First, homologous chromosomes are randomly divided into daughter cells, so many possible combinations of maternal and paternal chromosomes arise. Homologous recombination (sequence exchange) is the second way to increase genetic diversity.

What is chromatids? Definition

During cell division, these duplicates are connected to each other in an area called the centromere. After the combined sister chromatids are separated from each other in the anaphase of mitosis, each of them receives a new name - daughter chromosomes. What is chromatid in biology? Scientifically speaking, this is one of the 2 nucleoprotein strands that are formed when the chromosomes are doubled, which occurs during cell division. They are half of the two identical copies of the replicated chromosomes.

Formation of chromatids

Chromatin is DNA that is wound around proteins, thus forming spiral fibers. It is from these that the chromatids are formed. Before replication, the chromosome appears as a single-chain chromatid. After replication, it acquires a familiar X-shape. Each human cell contains 23 chromosome pairs, in total this number is 46 chromosomes.

Conclusion

It is customary to call a chromatid any of the two copies of the DNA molecule that together make up the chromosome, which was previously replicated and connected in an area called centromere. This name is used as long as these centromeres remain in direct contact. When the chromosomes are divided in the course of anaphase of mitosis or meiosis, filamentous chromatids become daughter chromosomes. Simply put, these are halves of replicated chromosomes.