Human Heredity

Human heredity is about how humans traits are passed on through generations. Several vocabulary words are related to the topic of human heredities, such as alleles, genotype, and variation. However, some of these words can be highly confusing and challenging. For example, it might be difficult to differentiate between alleles and genes. Thus, today, we will take a look at definitions of human heredity vocabulary.

Allele vs. Gene

Word	Allele	Gene
Definition	Different forms of a gene	A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristics of the offspring
Example	Blood type alleles: A, B, O	Blood type genes: type A, type B, type O, type AB

Dominant Alleles vs. Recessive Alleles

Word	Dominant Allele	Recessive Allele
Definition	A gene that expresses itself in the presence of the other (recessive) allele	A gene whose effect is not expressed unless there are two copies of recessive alleles in the organism
Example	Allele for brown eyes	Allele for blue eyes

Codominance vs. Incomplete Dominance

Word	Codominance	Incomplete Dominance
Definition	When two or more alleles are equally dominant	When organisms between two different phenotypes produce offspring that is a blending of the parental traits
Example	White flower crossed with a blue flower produces a flower that is white with blue stripes	Red flower crossed with a white flower produces a pink flower

Heterozygous vs. Homozygous

Word	Heterozygous	Homozygous
Definition	A pair of genes where one is dominant and one is recessive	A pair of genes were both are dominant or recessive
Example	One allele for brown eyes and one allele for blue eyes	Two alleles for brown eyes or two alleles for blue eyes

Genotype vs. Phenotype

Word	Genotype	Phenotype
Definition	Organism’s full hereditary information	Organism’s actual observed properties
Example	Two alleles for brown eyes	Brown eyes

Continuous Variation vs. Discrete Variation

Word	Continuous Variation	Discrete Variation
Definition	No limitation or value for variation	Variation that has distinct groups for organisms to belong to
Example	Height, weight	Eye color, blood type

 

Works cited:

“Standard Grade Bitesize Biology – Variation : Revision, Page 4.” BBC, BBC, http://www.bbc.co.uk/bitesize/standard/biology/inheritance/variation/revision/4/.

Miller and Levine Biology ©2010: A Biology Curriculum by Pearson, http://www.pearsonschool.com/index.cfm?locator=PSZxAa.