monozygotic (identical) twins would be produced when they develop from one zygote.
monozygotic (identical) twins would be produced when they develop from one zygote.
when would monozygotic (identical) twins be produced?
develop from one zygote
twin









































twins are two offspring produced by the same pregnancy. twins can be either "monozygotic" ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or "dizygotic" ('fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell.









































in contrast, a fetus that develops alone in the womb is called a "singleton", and the general term for one offspring of a multiple birth is "multiple". non-related look-alikes whose resemblance parallels that of twins are referred to as doppelgangers.









































section::::statistics.
twin
some research designs used in behavioural genetic research are variations on family designs (also known as pedigree designs), including twin studies and adoption studies. quantitative genetic modelling of individuals with known genetic relationships (e.g., parent-child, sibling, dizygotic and monozygotic twins) allows one to estimate to what extent genes and environment contribute to phenotypic differences among individuals. the basic intuition of the twin study is that monozygotic twins share 100% of their genome and dizygotic twins share, on average, 50% of their segregating genome. thus, differences between the two members of a monozygotic twin pair can only be due to differences in their environment, whereas dizygotic twins will differ from one another due to environment as well as genes. under this simplistic model, if dizygotic twins differ more than monozygotic twins it can only be attributable to genetic influences. an important assumption of the twin model is the equal environment assumption that monozygotic twins have the same shared environmental experiences as dizygotic twins. if, for example, monozygotic twins tend to have more similar experiences than dizygotic twins—and these experiences themselves are not genetically mediated through gene-environment correlation mechanisms—then monozygotic twins will tend to be more similar to one another than dizygotic twins for reasons that have nothing to do with genes.
behavioural genetics