When Elizabeth Gonzalez, MS, Senior Cytogeneticist, decided to create KaryoLogic back in 2008, she envisioned a mission of providing high quality chromosome karyotyping services to researchers across the globe. Her experience and professionalism led her to become Stem Genomics’ chosen partner for the US market. We asked her to tell us a bit more about G-Banding karyotype analysis, and to translate her experience into useful tips for scientists wanting to perform this traditional and well-recognized genomic stability assay.
- What makes scientists choose KaryoLogic?
Our aim is to respond quickly, and to make good recommendations and suggestions when appropriate. I believe we tend to go above and beyond the simple karyotyping analysis. To achieve that, we get involved in our clients’ projects and try and understand what they are seeking to achieve. Then we always give detailed answers.
- Without revealing your trade secrets, how can you explain your impressive 94% success rate* in G-Banding karyotyping and your fast turnaround time?
Hard work and attention to detail. It is important for us to observe the cells every day. We watch them grow under the microscope and make decisions as to when we should process them. Over time, we have developed an intuition that helps us make an educated guess as to when we need to start working with the cells. Sometimes it can be at odd times. If the right time is at night or during the weekend, we are prepared to come to the lab to attend to the cells.
- What tips would you have for our clients to increase their success rate when sending samples for karyotyping?
It’s best not to have too sparse or too dense a culture. If the cells are seeded too sparsely it won’t work. They need to have near neighbors, so if they are too thin in the culture they don’t do as well and tend to die out during shipping. At the other extreme, if the flask is nearly completely full, this will cause “contact inhibition”, slow the growth level down, and they will start to die out as well. The aim is to get to a 40-60% confluency in the flask upon arrival. One characteristic of very healthy stem cells is that they will continue to grow during shipping outside the incubator. Also, even if the cells are in a polystyrene box, they will respond to outside temperature and warm conditions. All this needs to be taken into consideration when sending your cells over for karyotyping analysis.
- What is the rarest cell type you have ever had to analyze?
Even though the great majority of our work is human karyotyping, a small proportion of our work is on rare species. The most interesting, rare cell type I have worked on would have to be the naked mole rat! A group was studying them in relation to aging and aging-related diseases. The mole rat can live up to 30 years, which makes it an interesting species to study closely. As for the most interesting, rare human cells I have worked with, it would have to be haploid cells. They have half the normal chromosome complement. So instead of having 46 chromosomes, they only have 23. I was surprised that these small cells could persist in culture.
- Why would you recommend that scientists complement their G-Banding analysis with a digital-based assay such as iCS-digital™ for human pluripotent stem cells?
It clearly reduces the limitations of the G-Band karyotyping. For the past 5 years, we have been aware of the frequent mutations in human pluripotent stem cells involving chromosome 20q. It is impossible to pick them up at the chromosomal level with G-Banding only, due to the lower resolution, which is why it is essential to couple G-banding with a more sensitive assay, such as iCS-digital™ PSC.
*over the last 2 years. The failures were predominantly due to received cells not passing QC1 (cells dead on arrival or contaminated with yeast).