Dizygotic twins, also known as fraternal twins, are siblings who develop from two different eggs that were fertilized by two different sperm cells. The spelling of the word "dizygotic" is often confusing due to its unusual combination of letters. In IPA phonetic transcription, it is pronounced as /daɪzɪˈɡɒtɪk/. The "di-" prefix means "two," the "zyg-" root refers to a fertilized egg or zygote, and the "-otic" suffix means "relating to." Thus, "dizygotic" literally means "relating to two separate fertilized eggs."
Dizygotic twins, also known as fraternal twins, refer to a pair of siblings who are conceived from two separate eggs fertilized by two different sperm cells at the same time. This biological phenomenon occurs when a woman simultaneously releases multiple eggs during ovulation, which are then fertilized by separate sperm cells. Dizygotic twins are characterized by their genetic dissimilarity, just like any other siblings, as they share approximately 50% of their DNA.
Unlike monozygotic twins (identical twins), dizygotic twins can be of the same or opposite sexes, and they may or may not resemble each other closely in physical appearance and other characteristics. As separate fertilization events take place, dizygotic twins can have different genetic traits, hair or eye colors, and even exhibit diverse personalities or abilities. Additionally, dizygotic twins are often observed to have separate amniotic sacs and placentas, resulting in distinct and independent development in the womb.
The occurrence of dizygotic twinning is influenced by various factors, including maternal age, hereditary factors, fertility treatments, and ethnic background. Dizygotic twinning is more prevalent in certain populations, such as African and West African ethnic groups, while less common in others. The frequency of dizygotic twinning can also be influenced by external factors, such as diet or use of fertility drugs.
Overall, dizygotic twins are a result of the simultaneous release and fertilization of two different eggs, leading to the birth of two offspring who share a womb during gestation but have diverse genetic compositions and individual characteristics.
The word "dizygotic" is derived from the Greek words "di" (meaning two) and "zygote" (meaning a fertilized ovum). "Dizygotic twins" is a term used in genetics and refers to twins who develop from two separate eggs fertilized by two different sperm, resulting in non-identical twins. In contrast, "monozygotic twins" are derived from a single fertilized egg that splits into two embryos, resulting in identical twins.