The coat color in Labrador retrievers is controlled by two sets of alleles. The gene E/e determines whether the fur has pigment or not and is epistatically dominant to the gene B/b, which controls the darkness of pigment when it is there. A breeder crosses a purebred black Lab with the genotype BBEE and a purebred yellow Lab with the genotype bbee, producing offspring that are black. A test cross is done between these offspring and an individual with the genotype bbee. What is the expected ratio of black:chocolate:yellow?

What is a traditional chinese touch therapy involving finger pressure applied to specific areas of the body to restore the flow of qi.

Did you know that a blue wales tongue weighs more than an elephant?

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?