Introduction: Cytogenetics

We’ve seen people undertaking a test for the determination of the gender of an unborn new member of the family. The gender reveal parties are joyful occasions of blues and pinks. The technique involved is usually called a prenatal cytogenetic test. But is that all that the test is used for?

Cytogenetic testing has become a norm for prenatal diagnosis to determine not just the gender but several other things like the physical and genetic health of the fetus, chromosomal abnormalities, etc. It is also heavily exploited to find the underlying causes of developmental disorders in children, for diagnosis of hematological cancers like chronic myeloid leukemia, for detection of genetic anomalies in congenital diseases, and in cases of multiple miscarriages to guide couples to make informed decisions for their future pregnancy. 

When Cytogenetics comes as such a stupendous tool to mankind, then what is the problem for students in learning about it?

We, at Labster, understand that science is magical yet complex. In order to simplify the complex science behind Cytogenetic testing, we take a leap to understand the cyclical problems faced by students year after year. We also comprehensively expand on how educators and teachers across the world can deal with those problems. Read on to find out how you can make the information handy for students in your next class. By the end of this article, we’ll share why a virtual lab simulation will prove useful not only for your students but also for you as an educator to deliver concepts more efficiently

3 reasons why Cytogenetics can be tricky to teach or learn

There are 3 major reasons why students dread and confuse the topic of Cytogenetic Testing. Acknowledging these blocks is the first step toward making the topic more approachable. 

1. Difficulty in merging the 2 distinct domains of Genetics and Cytology

Cytogenetics is an amalgamation of 2 distinct branches of Biology; cell biology and genetics. Students at both high school and university/college levels are often seen struggling with the basic concepts of both of these branches. In such a scenario, expecting them to interrelate the core concepts of both won’t be fair. Students find it particularly hard to understand how the chromosomes (genetics) relate to cell behavior (cytology).  While cytogenetic testing is based entirely on relating ‘abnormalities and alterations in chromosome number, banding patterns, shape, etc’ directly to the ‘cell behavior’, an inability to understand what’s exactly going on at both genetic and cellular levels leaves the students muddled and confused.

2. The techniques involved are extensive and convoluted

The techniques involved in the sample preparation and analysis are overwhelmingly extensive when they are theoretically introduced to the students. The convoluted methodologies and lack of understanding of their respective rationales tend to make the students hesitant about this subject. The list of techniques involved is also endless starting from traditional karyotyping and chromosomal banding (different types like G/Q/C/R/AgNOR) to modern molecular cytogenetic approaches like FISH (fluorescent in situ hybridization) and CGH (comparative genomic hybridization).

3. Lack of practical handling and visualization 

Though students admire the practical utility of cytogenetic testing, they still sometimes despise the subject due to the lack of manual handling experience and lab provisions. Facilities and consumables aren’t always available for all the techniques at the school or college level. For example, FISH requires fluorescent probes and fluorescent microscopes while schools and colleges usually have only a light microscope. The situation is further worsened by the dearth of any visual interactive tools to compensate for the lack of practical handling. 

5 ways to make Cytogenetic testing a more approachable topic to understand

In order to address the blocks encountered while teaching the Cytogenetic Testing techniques, educators can engage the under-listed solutions in their classes. These can help in overcoming the voids and current gaps in the teaching strategy that students find difficult to put with. Not only can they make teaching easier for educators like you but will also make lessons clearer and easier to assimilate for your students.

1. Make the core concepts of the subject and principles of techniques crystal clear

When you’re teaching a class about cytogenetics, your foremost attempt should be to demystify the Cytogenetics conundrum. Explaining how everything at the nucleotide level (molecular biology) translates to phenotypic display can be the first step. After that explain how cytogenetics can help in dealing with genetic material without sequencing it. Rather cytogenetic techniques deal with chromosomes as a whole. 

After this brief introduction, you can dive deeper and explain how different techniques work. We have listed some of the core principles from which you can take some leads.1. Karyotyping: Karyotyping can be explained as a cataloging procedure. In this, cytogeneticists freeze and capture images of all the unique chromosomes at the metaphase stage of mitosis. This systemized record of chromosomes is then cross-checked with a standard karyotype and an active hunt for chromosomal aberrations and abnormalities begins. Karyotyping can be useful in prenatal testing, detection of causes of recurrent miscarriages, genetic disease testing, family planning, oncological fields, and much more. 

2. FISH: FISH or fluorescence in situ hybridization can be explained as an advancement over the radioisotope-labeled probe-based hybridization technique. It has evolved to use fluorescent probes instead. You can explain why this technique became a regular clinical practice due to its higher safety levels of operation. 

3. CGH: CGH or comparative genomic hybridization can be introduced as further advancement in technology over karyotyping and FISH. With an improved resolution to detect chromosomal alterations and evading the need for cell cultures, CGH has become a routine practice in the diagnosis of prenatal genetic syndromes. 

An even more advanced version of CGH is “Array CGH” which uses DNA microarrays for faster and more specific (higher resolution) measurement of CNVs (copy number variations) in a locus-by-locus manner. You can use the Cytogenetics- perform a prenatal diagnosis simulation by Labster to gather active indulgence and participation of your students.

Figure: A snippet from the  Cytogenetics- perform a prenatal diagnosis simulation by Labster to educate your students about karyotyping steps. It is available for University/College classes.

Educating and regularly updating your students about the current advancements in the field can be a promising way to keep them intrigued about the subject. Further elaborations like these can help them understand why technology keeps evolving for the betterment of humankind and purposes.

2. Try to bridge the gap between theory and practical handling

Taking examples from real life where cytogenetic testing is employed on a daily basis can help in bridging the gap between theoretical and practical aspects of techniques. Look at the quoted examples that you can employ in your next class.

Example: Pregnancy Scans followed by Amniocentesis and Karyotyping

Expecting mothers usually time their 1st ultrasound in the 12th-14th week. It is also accompanied by an essential amniocentesis test for which amniotic fluid from the mother’s body is collected. The amniotic fluid being the source of some fetal tissues for examination, this test proves its ability to detect genetic abnormalities in the fetus. After this, explaining the intricacies of each step, reagent, and procedure involved becomes vital.  

• Explaining why cells are cultured before karyotyping becomes important.

• Explaining why colchicine is used in karyotyping is important.

• Explaining how Carnoy's fixative hardens the nucleic material is important. 

If not all the steps, you can at least demonstrate some steps in your classroom like the effect of colchicine on cells (it’s an anti-mitotic chemical). This will help your students grasp the lessons.

Figure: A snippet from the Cytogenetics- perform a prenatal diagnosis simulation by Labster showing an application of cytogenetic testing post ultrasound scans for expecting mothers. It is available for University/College classes.

3. Interest them with the examples of genetic disorders where cytogenetic testing proves its essence 

There are a number of genetic disorders which can be identified using cytogenetic tools. As your students connect the technique to the problems encountered in something as natural as human beings, they might get boosted to study more about the subject and maybe make contributions to this branch of science. 

You can list disorders like Down syndrome (related to intellectual disabilities), Edwards syndrome (related to issues with all the vital organs), Turner syndrome (related to under-development of female characteristics), etc- all of which can be diagnosed with cytogenetic testing. 

Such tests prove immensely useful as they buy some time for the patient’s family to ensure necessary precautions and take the best lines of treatment that’s available for the patient. 

Figure: Down’s Syndrome Karyotype. 

Image Source: https://wellcomecollection.org/works/wmcdanw6/images?id=ngu5s6vr

4. Simplify the analysis protocol using mind maps

The findings from cytogenetic testing are chromosomal abnormalities. They are very peculiar for each disorder. The different types of abnormalities are sometimes difficult to memorize for the students. As an effective measure, educators can help their students build mind maps for each of the disorders and the related findings from these tests. 

Example: Usually when employing the FISH technique in a clinical laboratory, two main types of underlying problems are being looked for. 

1. One of them being tumors. For oncological problems, point it out to your students that the usage of “interphase cells” is prominent. They are scored in “high number” so as to ensure that even a low level of “residual disease” isn’t present. 

2. The second type of problem is congenital disorders. For them, point out to your students that the usage of “metaphase cells” is prominent. They are scored in “low numbers” like 20-25 cells.  

Such a practice of making mind maps that relate the “technique”, “disorder” and “diagnosis rationale” can help your students in practically applying the lessons when required. 

Figure: A snippet from the Cytogenetics- perform a prenatal diagnosis simulation by Labster showing how to analyze the chromosomal aberrations in order to detect the underlying syndrome. It is available for University/College classes

5. Use virtual lab simulations

Since modern-day cytogenetic testing and techniques are clinically dominant practices requiring state-of-the-art infrastructure, the students of the subject usually suffer at the hands of ill-experience with the lab protocols. Moreover, the graphic illustrations or flowcharts of the techniques don’t equip the students appropriately. With virtual laboratory simulations from Labster, teachers can make more insightful points as students are rendered with better visual options where they can follow each step of the cytogenetic testing. The 3D simulations help them better understand how and why each reagent is added or step is performed. 

Your students don’t have to struggle to imagine how FISH or CGH or array CGH work in the clinical domain as our interactive Cytogenetics- perform a prenatal diagnosis simulation along with gamification elements come to the rescue. By using this way of active and immersive teaching, our virtual learning platform takes an advent in the field of Science to make the upcoming scientists thorough with the “basics of their respective subjects”. 

You can learn more about the Cytogenetics- perform a prenatal diagnosis simulation by here or get in touch to find out how you can start using virtual labs with your students.

Figure: A snippet from the Cytogenetics- perform a prenatal diagnosis simulation by Labster showing the cytogenetic testing facility (clinical set up). It is available for University/College classes