Karyotype of the Twin with Trisomy 21 (image) Université de Genève Share Print E-Mail Caption This is a karyotype of the twin with trisomy 21. Three copies of the chromosome 21 are present. Credit ©UNIGE - S. Antonarakis' lab Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.