Triploïdes

Triploïdes refers to an organism or cell that contains three sets of chromosomes instead of the usual two. This condition is known as triploidy. In sexually reproducing organisms, the normal chromosome number is diploid, meaning there are two complete sets of chromosomes, one inherited from each parent. Triploidy results from an error during fertilization or gamete formation, where either an egg or sperm cell contains an extra set of chromosomes, or when two sperm fertilize a single egg.

The presence of an extra chromosome set significantly impacts development. In humans, triploidy is a severe chromosomal abnormality and is almost always lethal. Pregnancies involving a triploid fetus are often miscarried early on. If a triploid individual survives to birth, they typically have multiple severe congenital abnormalities affecting various organ systems, including the heart, brain, and limbs. They also usually have distinctive facial features and significant intellectual disability. The prognosis for survival is very poor.

Triploidy can occur in other species as well. In some plants, triploidy can lead to larger fruits or flowers and is sometimes intentionally induced for horticultural purposes, such as in seedless watermelons. However, in animals, including humans, triploidy is generally considered a detrimental condition due to the profound developmental disruptions it causes. The viability of triploid individuals varies greatly depending on the species and the specific chromosomes involved.