Patterns of Inheritance

What are genotypes? The genotype is the description of an individual’s unique genetic makeup. The genotype can be used for the description of an entire genome or individual genes and their alleles.

Alleles are different forms of the same genes. In human beings, alleles of specific genes are coming in pairs. And our specific characteristics are all determined by combinations of alleles we all have.

The genotype of an individual is influencing their phenotype. A phenotype of an individual is the physical characteristics and traits of organisms resulting from their specific genetic makeup.

As an example, when we talk about the specific genotype for a person’s eye color, we could say that a person has 1 brown (B) eye allele and 1 (b) blue eye allele.

As a result, this individual’s phenotype is brown eyes.

That is since the specific allele for brown eyes is a dominant allele, whereas the allele for blue eyes is a recessive allele.

When an allele is dominant, it is the stronger version (variety) of a pair of alleles. A dominant allele shows its effect even when there is just one copy in an individual’s genome. In this example, the allele for brown eyes.

Alleles are recessive if a gene’s allele only shows its effect if there are 2 copies in an individual’s genome, As in our example, the allele for blue eyes.

(see image below).

What are phenotypes?

Phenotypes are descriptions of the physical characteristics and traits of organisms. If we talk, for example, about a person’s eye color, the phenotype of that individual could mean brown, blue, or green eyes.

Usually, a phenotype is influenced by a person’s genotype, though the environment can play a role as well (nature versus nurture).

1. A dominant gene usually shows itself over a ____.
A.
B.
C.
D.

Question 1 of 2

2. What is an example of a recessive human trait?
A.
B.
C.
D.

Question 2 of 2


 

Next lesson: Punnett Square

 

Last Updated on November 24, 2020.

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