Testis-determining factor (TDF), also known as
sex-determining region Y (SRY) protein, is a
DNA-binding
protein (also known as gene-regulatory protein/transcription factor) encoded by the
SRY gene that is responsible for the initiation of male sex determination in humans. SRY is an
intronless sex-determining
gene on the
Y chromosome in
therians (placental mammals and marsupials); mutations in this gene lead to a range of sex-related disorders with varying effects on an individual's phenotype and genotype.