twin chimera
Quick Summary
In genetics, a chimera is an organism or tissue containing at least two distinct sets of DNA, often resulting from the fusion of multiple zygotes (fertilized eggs). This differs from mosaics, which arise from a single zygote, and hybrids, which come from different species. Twin chimeras occur when two zygotes exchange cells and genetic material during development, leading to individuals with genetically distinct cell populations. A common example is blood chimerism in dizygotic twins, where blood stem cells transfer between fetuses via placental connections. This can lead to conditions like freemartin syndrome in cattle and intersex traits in humans.1
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