The Reverse Sorting Process Overview
What is reverse sorting?
Reverse sorting technology enables the sperm to be sorted for females or males, which is then used to create gender specific embryos in the Vytelle lab. This service is licensed and operated through ST Genetics within 6 of the 7 U.S. Vytelle labs.
When does reverse sort happen?
Reverse sorting happens the day of fertilization (day after OPU). Since the process takes approximately 3 hours per sort, the sorting process is started a few hours before the fertilization time to ensure an on-time fertilization.
How it works:
Step 1: Semen units are thawed and evaluated for concentration to identify how many million cells are in the units before proceeding. The reverse sorting process takes roughly 3 hours per sire which can be stressful on the semen so it’s important to begin with a high-quality sample.
Step 2: Based on the concentration of the sample, a specific amount of stain is added to the semen and allowed to absorb into the DNA of each sperm cell. This takes about 45 minutes. Sperm will be 50% male and 50% female with the differentiators being the chromosomes. Female sperm contain one X chromosome (X) while male sperm contain one Y chromosome (Y). This is important because X chromosomes contain a little more DNA than Y chromosomes which allows the female sperm cells to absorb more stain and fluoresce at a higher rate when placed on the reverse sorting machine.
Step 3: Once the sample is placed on the reverse sorting machine, the system orients sperm in a single file line and measures the fluorescence of each sperm cell with a laser. Once a sperm cell is identified as male, female, or dead it is deflected into the appropriate tube. The sorted semen is then used in our lab for fertilization. High-quality semen samples can yield a purity of 85 to 90%. For more information, visit ST Genetics website.
The million-dollar question:
Why is it required to have at least 2 units per reverse sort?
ST genetics requires at least 2 units of semen per reverse sort to ensure issues with the sample are mitigated from the beginning. Now that you have learned how the process works, you understand that at least half of the semen sample is either the undesired gender or is dead, which limits our viable, desired sperm cell count significantly from the beginning. Starting with an ample amount of semen can help ensure there are enough sperm cells to cover all of the oocytes once the sample is fully processed.
Technical Support
If you have any questions, please contact the Vytelle marketing team at [email protected]. For immediate assistance please contact your Vytelle Regional Sales Representative.
