Semen Sexing - Anatomy & Physiology

Principle

X and Y chromosomes contain different quantities of DNA.
X-bearing sperm contain 2.8-4.2% more DNA (species dependent) than Y-bearing sperm.
This allows them to be sorted into two subpopulations.
Separation requires the uptake of DNA stain/dye called Fluorochrome into living and dead sperm.
X-bearing sperm take up more dye than Y-bearing sperm.
Vital dyes emit light at a specific wavelength when excited or activated.
- X-bearing sperm will emit a larger signal than Y-bearing sperm.
This allows the sperm to be sorted by flow cytometry.

Ejaculated spermatozoa are treated with a DNA dye (fluorochrome).
X-bearing sperm absorb more dye than Y-bearing sperm.
X-bearing sperm thus emit more intense light when excited by a laser.
Sperm are also treated with a dye that greatly suppresses the signal from dead sperm.
- Dead sperm are therefore identified and rejected.