Karyotype Chart

Karyotype Chart

Use karyotype charts to look at chromosomes. This chart shows all the chromosomes paired up with one and other (homologous chromosomes). It is especially important to see nondisjunction.

Nondisjunction – In meiosis during anaphase one, when homologous chromosomes are pulled to opposite poles of the cell, sometimes, both chromosomes move to one pole of the cell. The result of this is a daughter cell with an extra chromosome and a daughter cell with a missing chromosomes. When gametes fuse during fertilization you can end up with an offspring with an extra chromosome, or an offspring with a missing chromosomes.

Normally you have 2 of each chromosome. An extra chromosome (3 in total) is called trisomy. An example of this is Down Syndrome = trisomy on chromosome 21.

Kleinfelter syndrome is another example of trisomy. In this situation you have 2 X chromosomes and a Y chromosome.

Monosomy is when you are missing a chromosome. Turner syndrome is the result of only one X chromosome (not 2^nd X, or Y chromosome).