Cannabis Biology: Genetics, Chromosomes, Phenotypes, and Genotypes

Photo Credit: NCCIH

Is it just me or do you often wonder, while enjoying a gram of Blue Dream, Chem Dawg, or Blue Lights,

how the heck did the Breeder come up with a seed that grows a cross between Blueberry and Haze (Blue Dream), or a cross between OG Kush and Sour Diesel (Chemdawg)”?

I’m an inquisitive Cannabis lover and so, if this happens when the high is from Blue Dream, I go down the rabbit whole a bit. Because from that question, others are born and then, I am looking for information and thinking about: what makes the plant female or male, Cannabis being a parent and how cool that is, and where the fragrance of the plant comes from.

If you have ever found yourself on one of those inquisitive Cannabis highs’ and asked/wondered: “how was this Sativa dominant hybrid strain, that has me on cloud 9 created?”, this one is for you. This is a quick guide to Cannabis biology genetics, chromosomes, phenotypes, genotypes, and terpenes.

This is a reposted piece, originally written by the author for CannaBliss Magazine, a Centennial Media publication. 

Cannabis Chromosomes

Looking at the plant as human, helped me make sense of the science/biology of Cannabis. Plant Cannabis magically mirrors human biology in a variety of ways. Like humans, Cannabis has lineage, a family tree, and chromosomes. 

Chromosomes are responsible for so much: they are a threadlike structure of nucleic acids and protein found in the nucleus of most living cells that carry genetic information in the form of genes. For both humans and Cannabis, the X and Y chromosomes, determine sex/gender (in western teachings).

Another similarity between humans and Cannabis is that they both receive an individual chromosome from a single mother and a single father. That combination creates the formation of genes, the segments of deoxyribonucleic acid, DNA, another thing Cannabis and humans have in common.

Cannabis Genotypes

Cannabis genotype is: the genetic makeup of the plant, and as Leafly refers to it, “the blueprint for growth”. Much like humans, the genotype is the product of mom+ dad= baby.

Have you heard people say “this isn’t the same type of cannabis that history talks about.”? Well, it could be because historical documents say that Cannabis originated in Central Asia, back in the B.C era, and Cannabis was not bred but instead, a wild grow. That was referred to as landrace, Cannabis strains that grow naturally in the wild in a specific geographic region on earth.

Current day, consider genotypes similar to the human version of baby making but instead of sex- a Breeder makes this happen by combining strains. Using Blue Dream as an example; the seed that is planted to grow Blue Dream, is created by a Breeder. In this stage, the genotype is being created by the breeder by using parents Blueberry- Indica and Haze- Sativa. Together, they will create an Indica, Sativa hybrid, giving birth to Blue Dream.

Cannabis Phenotype

Cannabis phenotype is: the visual/observable characteristics of the cannabis plant: height, shape, appearance, aroma, etc. Like humans, phenotypes are physical expressions that the environment pulls from them.

Basically, the environment pulls the plant’s physical traits from its genetic code. This is why plants from the same strain can end up providing different effects. Different environments and different growers, create their own unique physicality for each plant.

Royal Queen Seeds, a Cannabis seed company/provider provides the math: “the interaction between genotype and environment results in a phenotype: genotype (G) + environment (E) + genotype and environment interactions (GE) = phenotype (P)”.

Phenotypes are the reason why siblings with the same set of parents may resemble but aren’t identical, and why someone can get Blue Dream from California, but from two different growers, and have two different highs. Like Leafly says: “Cannabis phenotypes have different traits from one or both of their parent strains.

Bonus Insight- Cannabis Terpenes

Cannabis biology includes a lot, but I chose terpenes for bonus insight. 

Terpenes are: the aromatic compounds that give cannabis different scents. Cannabis is amazing! The plant produces terpenes and those terpenes protect the plant from insects. It does this by attracting insect predators to handle the insects so that the plant can thrive (herbivores love weed)!

Terpenes are dynamic and also contribute to the effects of each strain by working with, or should I say- influencing CBD, THC, and other cannabinoids. Terpenes have multiple benefits that help boost cannabinoid benefits.

For example, if someone is consuming Cannabis for anti-inflammation and anti-fungal reasons, that person would likely be a fan of a popular terpene: Myrcene, known as the mother of all cannabinoids and known for powerful antiseptic, anti-bacterial, anti-fungal, and anti- inflammation properties.

Cannasseurs like myself, smell the jar of bud prior to making a decision. We do this because the human nose knows which strain will be good for us- our bodies respond to terpenes the same they do with perfume/cologne fragrance. Terpenes are important, maybe even more than the potency percentage listed on the product label.


Cannabis biology intrigues me because I believe, and we are seeing more and more research surfacing, that Cannabis can treat almost every- if not every single condition. It mirrors human biology in many ways (we are also seeing that Cannabis is also effective pets) and so, I know I will sound like a typical lover of 420 everything but, it really does seem like Mother Earth, gifted Cannabis to specifically to treat mammal species.

Written by: Veronica Castillo