4.2 Genotype vs phenotype

The genotype of an organism is the genes it has. You can’t see them, and they are inherited from the parents of the organism (if sexual reproduction occurs). The phenotype is what results when the genes are expressed; for example, you have the genes (genotype) for attached earlobes, and the phenotype is you physically having attached earlobes. Some phenotypes can be seen with the naked eye, like hair and eye colour, while others are obscured, like blood type. Phenotypes are determined by genotype but can also be influenced by the environment (this is called epigenetics). For example, you might have inherited a predisposition for high cholesterol from your parents, but your diet can affect your cholesterol levels as well.

 

Schematic showing a chromosome containing many genes, which cause various biological mechanisms: produced protein or RNA has some direct function, an enzyme creates products that have some function, a transcription factor affects other genes that in turn have some function. These mechanisms result in the organism’s biochemical and physiological properties, developmental processes, morphology, behaviour and products of behaviour.
Figure 4.1 Genotype to phenotype: The sum of an organism’s genetic material along with its environment determine its phenotype. This is mediated via various biological mechanisms: either the direct activities of gene products or their downstream effects. Illustration by Thomas Shafee.

 

Phenotypes are determined by genotype but can also be influenced by the environment.

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