1. Methods of Detection Unit 6: Genetic Abnormalities IN 147

2. ULTRASOUND sound waves are used to generate an image of the unborn child. Used to detect abnormalities of limbs, organs, etc. sound waves are used to generate an image of the unborn child. Used to detect abnormalities of limbs, organs, etc. Also called sonogram Also called sonogram

3. Amniocentesis: fluid surrounding the fetus is drawn out by needle, fetal cells are collected and grown in a lab. Chromosomes can be then karyotyped Amniocentesis: fluid surrounding the fetus is drawn out by needle, fetal cells are collected and grown in a lab. Chromosomes can be then karyotyped

4. Chorion villi sampling: a sample of the chorion (membrane surrounding fetus) is taken, chemical tests and karyotyping are performed Chorion villi sampling: a sample of the chorion (membrane surrounding fetus) is taken, chemical tests and karyotyping are performed

5. Karyotyping: pictures of chromosomes are matched up according to size Karyotyping: pictures of chromosomes are matched up according to size

6. KARYOTYPING Karyotype: genetic organizing of pictures of chromosomes Karyotype: genetic organizing of pictures of chromosomes Arranged by banding patterns and by height. Arranged by banding patterns and by height. Enable us to determine the characteristics of a species, but not a particular organism. Enable us to determine the characteristics of a species, but not a particular organism. Steps to making a karyotype: Steps to making a karyotype: 1. Spread cells on water in order to make their membranes burst. 2. Inject a substance (colchicines) which stops mitosis by preventing cells from multiplying. 3. Take a photo of the preparation and classify the chromosomes by ascending height and if possible by pairs.

7. Classification by pairs depends on the species. The human karyotype is made up of 23 pairs of chromosomes (diploid). Classification by pairs depends on the species. The human karyotype is made up of 23 pairs of chromosomes (diploid). When a karyotype cannot be classified by pairs, the organism is called a haploid organism. When a karyotype cannot be classified by pairs, the organism is called a haploid organism. The twenty-third pair of chromosomes on a human karyotype is called the sexual chromosome pair. It specifies the sex of the person (XX for female The twenty-third pair of chromosomes on a human karyotype is called the sexual chromosome pair. It specifies the sex of the person (XX for female and, generally, XY and, generally, XY for male). for male).