Human karyotypes for teaching: (47, XY,+21, Trisomy 21) These karyotypes are from abnormal males. There is a full set of 23 homologous pairs of autosomes, and an X and Y, but an extra chromosome 21. These individuals are also said to have Down syndrome. Individuals with Down syndrome (formerly known as mongolism, from the commonly occuring skin fold on the medial side of the eye) are invariably mentally retarded, but are the most "normal" of any of the autosomal trisomies that survive to birth. There are many profound social questions arising from these births that provide abundant opportunity for class discussions. To transfer the image to your computer, click on the appropriate image name, and save it to your hard disk. ZooWeb Number Original image Modified image Key ZWK99011 ZWK99011o.jpeg ZWK99011.jpeg ZWK99011k.jpeg ZWK99012 ZWK99012o.jpeg ZWK99012.jpeg ZWK99012k.jpeg ZWK99024 ZWK99024o.jpeg ZWK99024.jpeg ZWK99024k.jpeg ZWK99025 ZWK99025o.jpeg ZWK99025.jpeg ZWK99025k.jpeg Each karyotype is available in one of three forms: The original unmodified smear. These may have extra material, and often have some chromosomes crossed, which makes them less useful for a class exercise in which students cut apart and arrange the individual chromosomes.. A copy of the original, with extraneous materials removed, crossed chromosomes separated, and all chromosomes separated slightly to faciliate cutting apart of the chromosomes in a printed copy. This form is intended for student use in an introductory biology class. A "key", with the chromosomes arranged in standard order. These karyotypes are from the Wisconsin State Laboratory of Hygiene. They are intended for use in teaching to help students study human chromosomes. Copyright for these images remains with the State Laboratory of Hygiene, apply to them for permission for any other use than non-profit teaching. For technical information on the methodology by which these smears were created click here. Karyotype_home Do you have suggestions for this page? Please contact one of the participants or email Larry Phelps (lphelps@uwc.edu) © 1998 The Board of Regents of the University of Wisconsin System. Click here to email comments regarding BioWeb or its links.