Blood Types Tutorial

What about the Rh factor?


Human ABO markers

Blood types and genotypes?

How are ABO alleles inherited by our children?

Blood type & Rh factor calculator

Blood type calculator

Rh factor

Problem set
The Rh factor genetic information is also inherited from our parents, but it is inherited independently of the ABO blood type alleles. There are 2 different alleles for the Rh factor known as Rh+ and Rh-.
Someone who is "Rh positive" or "Rh+" has at least one Rh+ allele, but could have two. Their genotype could be either Rh+/Rh+ or Rh+/Rh-. Someone who Rh- has a genotype of Rh-/Rh-.
Rh factor Possible genotypes
Rh+ Rh+/Rh+
Rh- Rh-/Rh-

Just like the ABO alleles, each biological parent donates one of their two Rh alleles to their child.
A mother who is Rh- can only pass an Rh- allele to her son or daughter. A father who is Rh+ could pass either an Rh+ or Rh- allele to his son or daughter. This couple could have Rh+ children (Rh- from mother and Rh+ from father) or Rh- children (Rh- from mother and Rh- from father).
Mother Father Child
Rh- Rh+ Rh+
Rh- Rh- Rh-

The Biology Project
University of Arizona
Thursday, October 23, 1997
Contact the Development Team
All contents copyright © 1997. All rights reserved.