How does genotype affect phenotype? Simple. Genotype is the collection of genes responsible for the various genetic traits of a given organism. Genotype refers specifically to the genes, not the traits; that is, the raw information in an organism’s DNA.
For example, two mice that look virtually identical could have different genotypes. But if they have visibly different traits – say, one has white fur and the other has black fur – then they have different phenotypes.
An organism’s genotype is the set of genes in its DNA responsible for a particular trait.
Genotype simply means what alleles are carried in a particular organism’s DNA. It can’t be determined by simple observation; it requires biological testing. Genotype is inherited from an organism’s parents and expresses all of the genetic information about it.
An organism’s phenotype is the physical expression of those genes.
Genotype is determined by the makeup of alleles, pairs of genes responsible for particular traits. An allele can be made up of two dominant genes, a dominant and a recessive gene, or two recessive genes. The combination of the two, and which one is dominant, determines what trait the allele will express.
For example, if you met someone with albinism you would know they most likely have a mutated TYR gene, because that’s the most common cause of albinism. That mutated TYR gene is part of their genotype. Albinism is part of their phenotype.
Phenotype is what you see – the visible or observable expression of the results of genes, combined with the environmental influence on an organism’s appearance or behavior. Everything from the shape of a bird’s wing to the song of a humpback whale can be considered part of the phenotype: observable aspects of that animal that are determined, at least in part, by its genes.
Genotype and phenotype are two fundamental terms in the science of genetics. The two terms are often used at the same time to describe the same organism, but there is a difference between genotype and phenotype:
Genotype refers to the genes responsible for a trait, phenotype is the visible result of those genes, as these examples of genotype and phenotype will demonstrate.
The story of one well-reputed strain, OG Kush, is a prime example for explaining the difference between genotype and phenotype. OG Kush was bred from cannabis seeds that originated from an accidental pollination of a cultivar called Emerald Triangle by a male Hindu Kush plant. The Floridian grower then brought a cutting to Southern California in the early ’90s. The cannabis he perpetuated from clones became very popular. These clones, which had identical genomes and were therefore of the same genotype, were grown in different locations across California and developed different phenotypes after exposure to their particular environments.
The way an organism physically expresses itself via its genetic makeup is its phenotype. All expressed, observable traits associated with an organism are that organism’s phenotype. The phenotype is a result of selective gene expression, or the ability to turn genes on or off. Genes may turn on or off depending on environmental conditions, which alter the organism’s phenotype. Terpene and cannabinoid profile, height, bud density, and leaf shape are all examples of phenotypic traits that can vary with different growing conditions, even within the same genotype.
Two plants with the same genetics that grow in different environmental conditions may lead to multiple phenotypes. (Photo by: Gina Coleman/Weedmaps)
At the basic level, the term genome refers to all of the genetic material of an organism, cell, or tissue. Coding DNA translates into proteins while noncoding DNA does not, therefore, not all DNA in the genome influences the development of an organism. Certain consequential sequences of DNA found within the entirety of an organism’s genome are considered that organism’s genotype. These sequences vary among individuals within the Cannabis sativa L. species.
Physical differences between clones are a consequence of exposure to different environmental conditions. This is called phenotypic plasticity. In other words, it is the ability of an organism to adapt to changing conditions of light, air, water, or nutrient levels. This is especially relevant for plants because they are typically stuck in one place and forced to adapt to their surroundings.
A plant’s phenotype is the way it physically expresses its genetic makeup. (Photo by: Gina Coleman/Weedmaps)
The origins of different cultivars of apples (Granny Smith, Honeycrisp, pink lady, etc.) have been thoroughly documented by the farmers that first bred them. However, the lineage of even the most famous cannabis cultivars, commonly referred to as strains , can be hazy due to the lack of documentation in an industry that still maintains its roots underground.
For example, in an area with limited sunlight, a plant’s leaves that were genetically predisposed to be narrow might start to grow wider and more broad to absorb as much light as possible. A clone of that exact plant, but grown in an area with a wealth of sunlight, may develop slender and more elongated leaves, as it will not need to compete so hard for the light. These plants’ abilities to alter their physical traits in order to thrive in their environments is an example of phenotypic plasticity. Plasticity accounts for the physical deviations among clones, which would otherwise be identical due to their shared genotype.
Growers who have received a clone from a breeder will receive a plant with the same genotype as the mother. But they will want to inquire closely about the growing conditions the breeder used to get the plant to express the desirable traits they were attracted to if they hope to grow a similar phenotype.
What’s the Difference Between Phenotype and Genotype? What You’ll Learn In This Article Genomes are only identical in the case of clones, but genotypes may be similar in seeds harvested