This lesson will cover the basics of heredity by looking at:
Heredity is the passing of traits from parents to offspring. Gregor Mendel is considered the father of genetics because he did a lot of work with heredity and examined how information is passed through generations from parent to offspring. Mendelian inheritance is a term that was coined due to his research on pea plants. It describes how genes are passed from parents to offspring. Genes are found on chromosomes and are passed from parents to offspring. They contain information about specific traits. Some different types of inheritance include:
Homologous chromosomes are chromosomes found within your cells that contain variations of the same information and are the same size and shape. A person will have one chromosome of this type from their mother and one from their father. A human has 46 total chromosomes in their body, 23 from each parent. Alleles are different versions of a gene, and you have two alleles for each trait, one on each homologous chromosome. The combination of alleles that you inherit will determine the outcome of that trait. A locus is a location on a chromosome where a trait will be located.
An example of a trait a person’s genes decides is their hairline. A person can have a straight hairline or they can have a widow's peak. This person has a pair of alleles at a specific locus, and each allele is a form of the gene for hairline.
Traits can be either dominant or recessive and recessive traits are only expressed when a dominant allele is not present. If a recessive allele is in the presence of a dominant allele, the dominant allele will always rule. There are three ways the mix of dominant and recessive alleles can present:
The prefix ‘homo’ means ‘“the same” and the prefix hetero means “different”
In genetics letters are used to represent the combinations of alleles. A capital letter is used to represent an allele that is dominant, and a lowercase letter to represent a recessive allele. Assume that the gene for having a widow’s peak is dominant. Now, there are two parent that both have heterozygous alleles for a widow’s peak. What are the possible phenotypes, or the physical manifestation of the genes you inherit, for each genotype going to be?If you have two parents that are both heterozygous, they could have children that are homozygous dominant, heterozygous, or homozygous recessive.
Heredity is the passing of traits from parents to offspring. Genes are the genetic information on chromosomes passes from parent to child, and alleles are the different versions of a gene. You inherited one from your mom, and one from your dad. Alleles can cause either dominant or recessive traits to be expressed. A dominate trait will always show if a person has the dominate allele. If a person is homozygous recessive, then the recessive trait will determine a person’s phenotype.
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Source: SOURCE: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND
Variation in a gene, an example would be eye color; there is a gene for eye color but there are different versions of genes that allow for different eye colors.
When one allele masks the expression of another on the same locus, this is seen at the phenotype level.
A genetic unit of heredity; a specific section of DNA that codes for a specific protein.
A trait or characteristic expressed at the genetic level, that is, the genetic makeup of an organism.
Dubbed the "father of modern genetics" and arguably modern biology, Mendel was an Austrian monk who studied heredity and inheritance in plants.
The passing of traits from parents to offspring.
An organism with two different alleles of a gene.
An organism with two identical alleles of a gene.
Receiving genetic characteristics from parents, the manner in which genes are passed down to offspring.
The term used to describe the specific location of a gene/DNA sequence on a chromosome; variations of these genes are referred to as alleles.
An observable characteristic of someone’s traits, examples: eye color, skin color, height, gender etc.
An allele that is masked by a dominant allele, recessive alleles are only expressed when they are found in homozygous pairs.