39. Karyotype - definition and evolution. The human karyotype.

Question 1

Karyotype:
- karyotype refers to the arrangement of chromosomes in homologous pairs

• the basis for the arrangement is the size of a chromosome, position of the centromere, and the chromosome - specific banding pattern
• the karyotype is characteristic for each species
• karyotype can also be applied to an individual or to a single cell

Answer 1

Karyotype:
- karyotype refers to the arrangement of chromosomes in homologous pairs

• the basis for the arrangement is the size of a chromosome, position of the centromere, and the chromosome - specific banding pattern
• the karyotype is characteristic for each species
• karyotype can also be applied to an individual or to a single cell

Question 2

Karyotype of man:

• karyotype responsible: 46, XX, 46, XY
• the 22 pairs of autosomes in man are divided into seven groups A - G

Answer 2

Karyotype of man:

• karyotype responsible: 46, XX, 46, XY
• the 22 pairs of autosomes in man are divided into seven groups A - G

Question 3

Flow cytometry karyotype in man:

• because of their different lengths, metaphase chromosomes can be presented in a flowcytometry - based karyotype
• individual chromosomes stained and passed by a laser light source, give signals corresponding to their sizes
• size of X chromosome lies between those of chromosomes 8 and 7, Y chromosome sizes differ considerably (close to size of chromosome 22)

Answer 3

Flow cytometry karyotype in man:

• because of their different lengths, metaphase chromosomes can be presented in a flowcytometry - based karyotype
• individual chromosomes stained and passed by a laser light source, give signals corresponding to their sizes
• size of X chromosome lies between those of chromosomes 8 and 7, Y chromosome sizes differ considerably (close to size of chromosome 22)

Question 4

• each chromosome pair and each chromosome segment of sufficient length has a recognisable band pattern, specific for the respective chromosome
• the possibility of identifying every chromosome region and many bands makes it possible to establish break points and to state the localisation of genes according to the region and band number on each chromosome

Answer 4

• each chromosome pair and each chromosome segment of sufficient length has a recognisable band pattern, specific for the respective chromosome
• the possibility of identifying every chromosome region and many bands makes it possible to establish break points and to state the localisation of genes according to the region and band number on each chromosome

Question 5

Specific metaphase chromosome identification:

• multiplex fluorescence in situ hybridisation
• spectral karyotyping

Answer 5

Specific metaphase chromosome identification:

• multiplex fluorescence in situ hybridisation
• spectral karyotyping

Question 6

Abnormal karyotypes:

45, X -> Turner’s syndrome

47, XY, +21 -> Trisomy 21 (down syndrome) 47, XXY -> Klinerfelter

47, 13 + -> Patau 47, 18 + -> Edwards

Answer 6

Abnormal karyotypes:

45, X -> Turner’s syndrome

47, XY, +21 -> Trisomy 21 (down syndrome) 47, XXY -> Klinerfelter

47, 13 + -> Patau 47, 18 + -> Edwards