Section 2
Patterns of Inheritance
Book
Version 32
By Boundless
By Boundless
Boundless Biology
Biology
by Boundless
6 concepts
![Thumbnail](../../../../../../figures.boundless-cdn.com/20183/square/bentoddjealousfamily.jpeg)
Genes as the Unit of Heredity
Genes exist in pairs within an organism, with one of each pair inherited from each parent.
![Thumbnail](../../../../../../figures.boundless-cdn.com/20286/square/mendel-s-20experiment.jpg)
Phenotypes and Genotypes
The observable traits expressed by an organism are referred to as its phenotype and its underlying genetic makeup is called its genotype.
![Thumbnail](../../../../../../figures.boundless-cdn.com/18911/square/figure-12-02-02.jpeg)
The Punnett Square Approach for a Monohybrid Cross
A Punnett square applies the rules of probability to predict the possible outcomes of a monohybrid cross and their expected frequencies.
![Thumbnail](../../../../../../figures.boundless-cdn.com/18915/square/figure-12-02-05.jpeg)
Alternatives to Dominance and Recessiveness
With the inclusion of incomplete dominance, codominance, multiple alleles, and mutant alleles, the inheritance of traits is complex process.
Sex-Linked Traits
A gene present on one of the sex chromosomes (X or Y in mammals) is a sex-linked trait because its expression depends on the sex of the individual.
![Thumbnail](../../../../../../figures.boundless-cdn.com/18934/square/figure-12-02-10.jpeg)
Lethal Inheritance Patterns
Inheriting two copies of mutated genes that are nonfunctional can have lethal consequences.