Difference between X and Y Chromosome

 X vs Y Chromosome in Humans

Both X and Y chromosomes are called Allosomes or sex chromosomes.

They are quite different in size, shape, and number of genes. In males; X and Y chromosomes are the only chromosome pair which is non homologous.

Watch our 2 minute video: Difference between X and Y chromosome

X chromosome	Y Chromosome
Size: Large (approx. 155 million base pairs).	Small (roughly 59 million base pairs).
Morphology: Submetacentric (centromere is slightly off-center).	Acrocentric (centromere is near the very top).
Gene number: High (800–900 protein-coding genes).	Low 60–100 protein-coding genes.
Primary Function: Contains genes for female development and vital non-sex traits (e.g., blood clotting, color vision).	Contains the "master switch" for male development (SRY gene that code the Testis-Determining Factor (TDF) protein, a transcription factor that triggers embryonic gonads to develop into testes
Presence: Found in both males (XY) and females (XX).	Found only in males (XY).
Inactivation: One X is inactivated in females (Barr body).	Does not undergo inactivation.
Survival: Essential for life (no human can survive without at least one X).	Not essential for life (females can live without it).