Its call a niche hope this helps :)
Myocardial conduction cells are connected by cardiac muscle tissues
A. occurs mostly in males. Females may exhibit symptoms but rarely. Female carriers are asymptomatic (not affected). Characteristic cannot be transmitted male to male. Affected males transmit the trait to all daughters.
This means that each dominant allele "adds" to the expression of the next dominant allele. Usually, traits are polygenic when there is wide variation in the trait. For example, humans can be many different sizes. Height is a polygenic trait, controlled by at least three genes with six alleles.
