kromosomikokonaisuus

Kromosomikokonaisuus refers to the complete set of chromosomes found within a cell or an organism. In eukaryotes, this typically includes both the nuclear chromosomes, which contain the vast majority of the genetic material, and mitochondrial chromosomes, which are found in the mitochondria and carry genes involved in cellular respiration. The number and structure of chromosomes are characteristic of a species. For example, humans normally have 23 pairs of chromosomes in their somatic cells, totaling 46 chromosomes. This includes 22 pairs of autosomes and one pair of sex chromosomes (XX for females and XY for males). Gametes, such as sperm and egg cells, are haploid, meaning they contain only half the number of chromosomes found in somatic cells. The organization of chromosomes within the nucleus, including how they are packaged with proteins called histones to form chromatin, is crucial for regulating gene expression and ensuring accurate DNA replication and segregation during cell division. Aberrations in the chromosomal composition, such as aneuploidy (an abnormal number of chromosomes) or structural rearrangements (like translocations or deletions), can lead to developmental disorders and diseases.