An example of a chromosome number is 46, which is the diploid number (2n) in humans. This represents 23 pairs of chromosomes.
Understanding Chromosome Numbers
Chromosome number refers to the total number of chromosomes present in the nucleus of a cell. This number is consistent within a species, but it varies greatly across different species. The diploid number (2n) represents the total number of chromosomes in a somatic (non-sex) cell, while the haploid number (n) represents the number of chromosomes in a gamete (sperm or egg cell).
Examples of Chromosome Numbers in Different Organisms
As highlighted in the reference material, chromosome number does not correlate with the apparent complexity of an organism.
| Organism | Diploid Number (2n) | Pairs |
|---|---|---|
| Humans | 46 | 23 |
| Dog | 78 | 39 |
| Common Earthworm | 36 | 18 |
Factors Affecting Chromosome Number
Although chromosome number is generally constant within a species, variations can occur due to:
- Polyploidy: Having more than two sets of chromosomes.
- Aneuploidy: Having an abnormal number of chromosomes, either more or less than the normal diploid number.
These variations can sometimes lead to genetic disorders or contribute to the evolution of new species.
