Karyotyping

• A picture is taken of chromosomes during mitosis

Karyotyping• A picture is taken of chromosomes during

mitosis

• Chromosomes are cut out and grouped in pairs• Karyotyping is lining up homologous pairs of

chromosomes• We know they are homologous pairs because they

are the same size and have the same banding pattern on them. (meaning those lines on the chromosomes) Look at the example of a kayrotype in the next slide.

• That was a picture of an individual that didn’t have any extra chromosomes or missing chromosomes.

• Now lets look at a karyotype and you can try and guess if there is anything different about it…

•So what did you see on the karyotype?

Down Syndrome• Trisomy 21 meaning an extra 21 chromosome

• Traits of these individuals are:

• Lower than average mental ability

• Single crease across the palm

• Almond shaped eyes

• Now look for a difference in the next slide…what is different?

Edwards Syndrome

• Trisomy 18 (extra 18th chromosome)

• Traits of these individuals are:

• severe growth retardation

• Microcephaly (micro= small, cephaly=brain)

• malformed ears

• distinctively clenched fingers

Edwards Syndrome

• Now look for a difference in the next slide…what is different?

Patau Syndrome

• Trisomy 13 (extra 13th chromosome)• It is rare for fetuses with this condition to go

to term• only 1 in 6000 live births. It is rare for babies

to survive for very long because of the complications that are usually present.

• cleft lip • Polydactyly of all extremities (meaning extra

fingers or toes)• Cyclopia (one eye)

Patau Syndrome

• This baby has a cleft palate, atrial septal defect, inguinal hernia, and postaxial polydactyly of the left hand

Patau Syndrome

• At 7 years old (survival beyond the first year is uncommon) this boy is deaf and legally blind.

• Now look for a difference in the next slides…what is different?

• The end