Karyotype Memes

This meme is playing on the classic "we have food at home" parental response, but with a genetic twist! The joke is about Down syndrome (Trisomy 21), where instead of the normal two copies of chromosome 21, a person has three copies. The karyotype image shows the "chromosome 21 at home" with a circled third copy of chromosome 21, which is exactly what causes Down syndrome! It's like when you ask for McDonald's and your mom says "we have food at home," except in this case, the embryo is asking for an extra chromosome and doesn't realize it's already getting one! The genetic equivalent of being careful what you wish for because you just might get it—three times over!