The key difference between pedigree and karyotype is that pedigree is the representation of the pattern of inheritance of a particular trait among the members of the same family while karyotype is a diagram which shows the chromosomal number and constitution in the cell nucleus of an individual.
Pedigree represents the family history of a particular trait, especially the inheritance of a gene. A karyotype is a diagram that shows the chromosomal number and constitution in the cell nucleus of an individual. It reveals information regarding the number, size, shape, centromere position of the chromosomes, etc. under a light microscope. Both pedigree and karyotype provide important information regarding genetic diseases.
CONTENTS
1. Overview and Key Difference
2. What is Pedigree
3. What is Karyotype
4. Similarities Between Pedigree and Karyotype
5. Side by Side Comparison – Pedigree vs Karyotype in Tabular Form
6. Summary
What is Pedigree?
A pedigree chart represents the genetic family history of a particular trait. It is useful to determine the risk and presence of a disease in the next generation. Therefore, the purpose of pedigree is to analyze the inheritance of a particular trait among the members of the same family. This analysis is usually done for three generations or more.
Figure 01: Pedigree Analysis
In pedigree analysis, marriages are represented by lines. Males are represented by boxes, while females are represented by circles. If the analyzed trait is present in any individual, it is represented in black or shaded. Moreover, it reveals whether the trait is dominant or recessive. Furthermore, a pedigree chart indicates whether the trait resides in the autosomes or sex chromosomes. It also shows the mode of inheritance of a trait in the family. Most importantly, pedigree has the ability to identify conditions like haemophilia or colour blindness in advance in the coming generations.
What is a Karyotype?
A karyotype is a diagram which shows the correct number and structure of the complete set of chromosomes in a cell of an individual. In the human genome, there are 23 homologous chromosome pairs. Among the 23 pairs, 22 are autosomal chromosome pairs while one is a sex chromosome. Each chromosome has a specific size, shape and centromere position. Karyotype of a healthy human does not have missing sequences or changes in genetic information.
Figure 02: Karyotype
By analyzing the karyotype of an organism, it is possible to detect genetic disorders and many other information about the individual. It can indicate the gender of the individual and the species to which the individual belongs to. Finally, karyotype can reveal whether the individual has a chromosomal disorder which leads to a genetic disease.
Karyotyping is a technique performed by doctors to examine the complete set of chromosomes in the nucleus. Chromosomes are visible only during the metaphase of the cell division. Total chromosomes are collected and analyzed during the test to determine whether there are numerical or structural abnormalities in chromosomes of an organism.
What are the Similarities Between Pedigree and Karyotype?
- Both pedigree and karyotype are based on chromosomes and genes.
- They are important in detecting genetic disorders.
What is the Difference Between Pedigree and Karyotype?
A pedigree chart shows the pattern of inheritance of a particular trait within a family. Meanwhile, a karyotype is a visual image of the number and appearance of the chromosomes in a cell nucleus. So, this is the key difference between pedigree and karyotype. Besides, a pedigree chart is drawn considering three or more generations while karyotype is drawn for an individual.
Moreover, pedigree analyses genes, while karyotype does not analyze genes. In addition to this, karyotype reveals chromosome aberration, while pedigree does not.
The below infographic tabulates the difference between pedigree and karyotype.
Summary – Pedigree vs Karyotype
Both pedigree and karyotype are important in understanding genetic diseases. Pedigree charts show the presence and absence or pattern of the inheritance of a particular trait among the members of a family. A pedigree chart is drawn using information about three or more generations of the family. Karyotype, on the other hand, is an image that shows the number and appearance of the chromosomes of the nucleus of an individual. Hence, pedigree analyses a trait (inheritance of genes) while karyotype analyses chromosomes. Thus, this summarizes the difference between pedigree and karyotype.
Reference:
1. Griffiths, Anthony et al. “Human Pedigree Analysis”. Ncbi.Nlm.Nih.Gov, 2020, Available here.
2. “Karyotyping | Learn Science At Scitable”. Nature.Com, 2020, Available here.
Image Courtesy:
1. “PedigreechartC” (CC BY-SA 3.0) via Commons Wikimedia
2. “Karyotype” By Can H. (CC BY 2.0) via Flickr
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