Genetic Inheritance

Inheritance Patterns

These examples are oversimplified, and as always, genetics is much more complex.

Dominant-Recessive

Dominant-Recessive genes are what you generally learn in school. There is a dominant allele, and a recessive allele. If there is a dominant allele present, then you get the dominant, but if there is only recessive alleles present, then you get the recessive trait. This shows in eye colors of humans.

Dominant-Recessive Inheritance

Incomplete

Incomplete dominance is when neither allele is fully dominant in a organism with two different alleles (heterozygous). It causes a blended/intermediate phenotype. An example of these are the color of petals on flowers.

Incomplete Inheritance

Co-Dominance

Co-Dominance occurs when both genes are dominant, and both traits show up. An example of this is cow fur.

Co-Dominance Inheritance

X-Linked (Recessive)

X-Linked Recessive traits are traits that are passed down through mutations in the X chromosome. Due to it being recessive, requiring all X chromosomes to have that mutation, more males are affected than females, due to males only having one X chromosome. Females can be carriers of this trait though, as the the X chromosome from females does pass down to future generations.

X-Linked Inheritance

X-Linked (Dominant) (Not Simulated)

X-Linked Dominant traits are traits that are passed down through mutations in the X chromesome. Due to it being dominant, it only requires one X chromesome to be mutated to exist. This means more females are affected than males.

X-Linked Dominant Inheritance

Simulation

Below is an interactive simulator to explore genetic inheritance:

Each trait that the bean has simulates a different inheritance pattern. By clicking New Generation, you create a random (or custom) partner for the bean, and then a offspring is made from those two beans.

Hands: Dominant-Recessive

Legs: Incomplete Dominance

Color: Co-Dominance

Gender & X Linked: Head Color (Yellow is Male, Black is Female, and Green is X linked mutation)

View on Github

Sources

“Understanding Genetics: A District of Columbia Guide for Patients and Health Professionals.” National Library of Medicine, https://www.ncbi.nlm.nih.gov/books/NBK132145