What is karyotype

Sex Chromosomes and Sex Determination. Sex Chromosomes in Mammals: X Inactivation. Sex Determination in Honeybees. Citation: O'Connor, C. Nature Education 1 1 Each chromosome pair viewed in a karyotype appears to have its own distinct "bar code" of bands. What changes do scientists look for in a karyotype when diagnosing diseases and disorders? Aa Aa Aa. Preparing Karyotypes from Mitotic Cells. The process of generating a karyotype begins with the short-term culture of cells derived from a specimen.

After a period of cell growth and multiplication, dividing cells are arrested in metaphase by addition of colchicine, which poisons the mitotic spindle. The cells are next treated with a hypotonic solution that causes their nuclei to swell and the cells to burst. The nuclei are then treated with a chemical fixative, dropped on a glass slide, and treated with various stains that reveal structural features of the chromosomes. Figure 1: Chromosome banding revealed by different staining techniques.

Different chromosomal staining techniques reveal variations in chromosome structure. Cytogeneticists use these patterns to recognize the differences between chromosomes and enable them to link different disease phenotypes to chromosomal abnormalities. Giemsa banding a , Q-banding b , R-banding c and C-banding d are shown. Chromosome translocations. Nature Reviews Cancer 1, ; Stamatoullas, A. Conventional cytogenetics of nodular lymphocyte-predominant Hodgkin's lymphoma.

Leukemia 21, ; Vega, H. Roberts syndrome is caused by mutations in ESCO2 , a human homolog of yeast ECO1 that is essential for the establishment of sister chromatid cohesion. Nature Genetics 35, All rights reserved. Figure Detail. Organizing Chromosomes in Karyograms for Review. Using Karyograms to Detect Chromosomal Abnormalities. References and Recommended Reading Caspersson, T. Nature Genetics 12 , — link to article Strachan, T. Wiley, New York, Tjio, J. Hereditas 42 , 1—6 Trask, B. Article History Close.

Share Cancel. Revoke Cancel. Keywords Keywords for this Article. Save Cancel. Flag Inappropriate The Content is: Objectionable. Flag Content Cancel. Email your Friend. Submit Cancel. This content is currently under construction.

Explore This Subject. Chromosome Analysis. Chromosome Structure. The synteny relationship conservation of gene order among different species is well known, and the positional effect and the importance of order of genes within a gene cluster is well appreciated e.

Recently, the significance of order of genes has been illustrated in synthetic biology Heng, Chromosomal alterations e. It also can trigger genome instability to produce further chromosomal changes.

Changing the coding is a common mechanism for new genome formation for both organismal and somatic evolution. Chromosomal re-organization creates new emergent information and is the most effective way of creating new and sometimes drastically different phenotypes. A given gene can have different functions within different genomic topology, exhibited through increased or reduced activity, as well as new genomic interaction with other genes, which can change its function.

The same protein can have different functions when located in different regions of the cell, with different partners, or when involving different pathways. It is also possible that different cellular sites of protein synthesis are function specific. Nevertheless, most genes are known to work in this context-dependent manner. The genomic topology serves as such context.

Different karyotypes can have similar phenotypes as long as some functional modules are preserved within an altered genome. There is a gene and karyotype interaction both collaboration and conflict. The change of genomic context also includes gene—promoter interaction. For example, the capture of an aerobic promoter by Escherichia coli with a previously anaerobic or unexpressed citrate transporter leads to a novel phenotype van Hofwegen et al.

Fuzzy inheritance can be detected from the chromosomal coding level as well. Inheritance is a key feature for all biosystems.

Establishing the correct mechanism for how biosystems create, and then pass on, their information is of utmost importance for both basic genomic research and its application for medicine. It is long accepted that the gene defines bio-inheritance. The concept of karyotype coding effectively addresses the issue of missing heritability. This key genome factor likely accounts for a large portion of the missing heritability, even though the fuzzy inheritance at gene level is also contributing to the phenomenon.

In addition, system inheritance also defines the boundary of the epigenetic regulation; equally important, there is a gap between germline-defined inheritance and the environmental-influenced somatic inheritance such emergent properties are highly dynamic and constantly changing in response to development, aging, and cellular stress. Karyotype coding unifies organismal evolution and somatic evolution, as both evolutions need to pass system inheritance and involve macro- and microevolution.

They share the same two phases of macro- and microevolution despite the different mechanisms used to maintain system inheritance.

It also explains why cancer can happen within 20—30 years while organismal evolution takes much longer though initial speciation can be quick, it often takes a long time to form a stable population.

Without the genome constraint ensured by sexual reproduction, the genome chaos can fast become dominant in somatic evolution, leading to cancer Heng, In contrast, the function of sex provides the strong genome constraint in organismal evolution. For a successful speciation, it requires three highly rare events: genome re-organization to produce survivable individuals with altered genome; the availability of other mating partners with a matching genome producing fertile offspring ; and the initial small population growing into a visible population Heng, The model Figure 1 unifies diverse molecular mechanisms of genome variations.

Examples of supporting evidences are listed in Table 1. More examples can be found in the book Genome Chaos Heng, Recently, the importance of chromosomal research has become more obvious. For example, chromosomal abnormalities are copious in cancer including various types of genome chaos, and predicting clinical outcomes based on chromosomal data is much better than based on DNA sequencing data Davoli et al.

In addition, chromosomal and nuclear aberrations have been linked to immune response Mackenzie et al. The stochastic chromosomal changes, such as non-clonal chromosome aberrations NCCAs , are used to measure chromosomal instability CIN and to explain treatment outcomes Heng et al.

Now, it is increasingly clear why high levels of NCCAs should not be ignored, as they reflect the system instability. Furthermore, the evolutionary meaning of altering the chromosomal coding is also applied to the study of other disease types, and organismal evolutionary studies Heng, ; Heng, With the introduction of the chromosomal-coding concept, the following tasks need to be achieved to maturate this concept:.

Further illustrate the molecular details of karyotype coding:. As illustrated in Figure 1 , the model of genome-topology based inheritance does not offer molecular details of how karyotype coding works. Further, chromosomal coding may involve more complicated mechanisms due to the large-scale organization, which likely involves emergent behavior. Moreover, the altered evolutionary potential needs to be studied with these changes. Illustrate the relationship among different types of bio-inheritance:.

To illustrate the significance of karyotype coding, quantitative and comparative studies are needed to rank the contribution of different types of inheritance under different bioprocesses and environments. The following solutions are needed when systematically comparing different types of bio-inheritance: separating germline and somatic cells germline with the highest constraint, the somatic cell with highest dynamic changes to compare the germline profile with tissue-specific somatic cell profiles; separating profiles of individual cells and cellular populations; separating the two phases of cancer evolution cancer formation by creating new genome systems; microevolution to increase the number of cancer systems, by stochastically capturing the oncogenes Ye et al.

Study mechanisms of organismal macro-evolution and how changes in karyotype coding can create new species:. While the model of how karyotype change leads to speciation has been proposed Heng, b ; Heng, , it has a long way to go before the research community accepts it. Many questions need to be addressed, for example: How universal is chromosomal coding to define species knowing that it is rather common in angiosperms and in animals Murphy et al.

How are we to define species without typical chromosomal coding? Answering these questions requires an understanding of how genome-based information is packaged and regulated. The following approaches are useful: 1 creation of a testable model for the chromosomal code, 2 mechanistic study of chromosomal reshuffling to create new emergent information in evolution, and 3 development of working models where the new emergent genomic topology with the same gene materials drives a phenotype.

In fact, the suggested chromosome shuffling experiments were already partly performed in yeast see Table 1. Clinical implications. Studying karyotype coding has clinical significance. Besides cancer prediction, it can potentially be used in many common and complex diseases. For example, chromosome instability has been proposed as a new general feature for diseases caused by cellular adaptation and its trade-off see Horne et al.

Somatic mosaicism needs to be considered as well as it can alter the phenotypes. Equally important, the combination of system inheritance and the fuzzy inheritance will provide a deep understanding of how environmental interaction contributes to disease phenotype based on the genome—environment interaction. LS and GL participated in the discussion, literature search, and editing of the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

We thank Jessica Mercer for editing the manuscript and Dr. James Shapiro for making suggestions. Ao, P. Towards predictive stochastic dynamical modeling of cancer genesis and progression. Interdisciplinary Sci. Bakhoum, S. Chromosomal instability drives metastasis through a cytosolic DNA response. Nature , — Biesecker, L.

A genomic view of mosaicism and human disease. Bloomfield, M. Your provider will collect cells from the placenta in one of two ways: either through your cervix with a thin tube called a catheter, or with a thin needle through your abdomen. CVS is usually done between week 10 and 13 of pregnancy.

For this test: You'll lie on your side or your stomach, depending on which bone will be used for testing.

Most bone marrow tests are taken from the hip bone. The site will be cleaned with an antiseptic. You will get an injection of a numbing solution.

Once the area is numb, the health care provider will take the sample. For a bone marrow aspiration, which is usually performed first, the health care provider will insert a needle through the bone and pull out bone marrow fluid and cells.

You may feel a sharp but brief pain when the needle is inserted. For a bone marrow biopsy, the health care provider will use a special tool that twists into the bone to take out a sample of bone marrow tissue. You may feel some pressure on the site while the sample is being taken.

Will I need to do anything to prepare for the test? You don't need any special preparation for karyotype testing. Are there any risks to the test? What do the results mean? Some disorders caused by chromosomal defects include: Down syndrome , a disorder that causes intellectual disabilities and developmental delays Edwards syndrome, a disorder that causes severe problems in the heart, lungs, and kidneys Turner syndrome , a disorder in girls that affects the development of female characteristics If you were tested because you have a certain type of cancer or blood disorder, your results can show whether or not your condition is caused by a chromosomal defect.

Is there anything else I need to know about a karyotype test? Washington D. Atlanta: American Cancer Society Inc. Amniocentesis; [updated Sep 2; cited Jun 22]; [about 2 screens].

Atlanta: U. C: American Association for Clinical Chemistry; c— Chromosome Analysis Karyotyping ; [updated Jun 22; cited Jun 22]; [about 2 screens]. Down Syndrome; [updated Feb 28; cited Jun 22]; [about 2 screens]. The karyotype is used to look for abnormal numbers or structures of chromosomes.

When I hear the word "karyotype", I think about a picture of chromosomes. When somebody has their blood studied to look at how many chromosomes they have and whether the chromosomes are complete, we come up with a picture in which we can line up all the chromosomes and count them.