Concept explainers
To analyze:
Visual of human chromosome
Introduction:
Chromosome mapping is the arrangement of the chromosomes. Genetic mapping provides the clue about the position, structure and, location of the chromosomes.
To study the cytogenetics of chromosome; the G-banding or Giemsa banding technique is used. A karyotype is the arrangement and appearance of the chromosomes in the nucleus of the eukaryotic cell. Karyotyping specifically did to study the number of chromosomes, positions, banding pattern or differences between the sex chromosomes.
It is very challenging to figure out these aspects with simple staining procedures that applies uniform color to all structures or parts of the chromosome.
Hence, G-banding technique was developed that specifically highlights light and dark bands.
G-Banding is useful in the detection of genetic diseases through photographic visualizations of the entire chromosome.
In this technique- the metaphase chromosomes are partly digested and treated with trypsin, later stained with the Giemsa stain.
The dark bands refer to the rich A and T regions while light regions refer to the G and C rich regions.
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Genetic Analysis: An Integrated Approach (3rd Edition)
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- The average human chromosome contains about 1 x 108 bp of DNA.(a) If each base pair has a mass of about 660 daltons and there are about 2 g of protein (histones plus nonhistones) per gram of DNA, how much doessuch a chromosome weigh (in grams)?(b) If the DNA were extended, how long would it be?(c) An actual chromosome is about 5 mm long. What is the approximatecompaction ratio?(d) You have about 4 x 1012 cells in your body. If you have 46 chromosomes in each cell, what is the approximate extended length of all of your DNA? For comparison, the distance from the earth to the sun isabout 1.5 x 108 km.arrow_forwardDiploid Number of chromosomes, Sex Chromosomes, (+/- whole) Chromosome (+/- partial) e.g. 47, XY, +14 = male with trisomy of chromosome 14 e.g. 46, XX, 1q+ = female with a partial increase to the length of the long arm of chromosome 1 (partial increases or decreases to a single chromosome still have the same diploid number) What is the notation for the following cases? ( A male infant having cri du chat syndrome.arrow_forwardDiploid Number of chromosomes, Sex Chromosomes, (+/- whole) Chromosome (+/- partial) e.g. 47, XY, +14 = male with trisomy of chromosome 14 e.g. 46, XX, 1q+ = female with a partial increase to the length of the long arm of chromosome 1 (partial increases or decreases to a single chromosome still have the same diploid number) What is the notation for the following cases? ( A male having Patau syndrome (trisomy 13)arrow_forward
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