Question

1. How is race/ethnicity defined genetically and phenotypically? Is it even possible to define race/ethnicity by genetics?
2. How does it help or hinder health care when sickle cell is considered a disease of individuals of African-descent?

Answer 1

Subspecies are an independent evolutionary branch of species. It may be formed by geographical isolation. Accumulation of variation above threshold or mutation with natural selection leads to its formation. All the human races are arises from common evolutionary descent. So the presence of subspecies in humans is absent. Races concepts are socially constructed in humans. So in the case of humans races concepts may not be defined genetically.

Sickle cell anemia is mainly present in tropical regions like Africa. They are now migrated to other countries because of the migration of the population. It is an autosomal recessive trait. In the beta chain of hemoglobin at its 6th position glutamic acid is replaced by valine.

Male/Female	Hbn	Hbs
Hbn	HbnHbn	HbnHbs
Hbs	HbnHbs	HbsHbs

Phenotypic: Genotypic

HbnHbn-Normal (Homozygous) 1 : 1

HbnHbs-Normal(Heterozygous) 2 : 2

HbsHbs-Dead(Lethal)

In this case Shape of RBC becomes deformed. Less O2 Carrying capacity. In a heterozygous state its expression is hampered. This is one of the adaptation to control its propagation of survivorship in progeny.