Heredity (Genetic Code) — Characteristics of Life

What Is the "Universal Genetic Code"?

All living things possess genetic information that they can pass on to their offspring.

In fact, every living thing keeps its genetic information in DNA (deoxyribonucleic acid) or RNA (ribonucleic acid).

This is why we call DNA and RNA the universal genetic code. Literally every organism on Earth has their genetic code written in this same "language". That's why scientists can take the genetic material from one animal and put it into another animal in genetic engineering.

This shared genetic code supports the idea that all organisms evolved from a common ancestor a really long time ago.

Inherited Traits

You know how people say, "I got my eyes from my dad" or "I got my curly hair from my grandmother"? They're talking about inherited traits. Things that get passed from parents to offspring in DNA are inherited. Inherited traits can also be called hereditary.

Recall that in organisms that use asexual reproduction, offspring are clones of their parents. They inherit DNA that is identical to their parent's.

On the other hand, in organisms that use sexual reproduction, offspring inherit a combination of their parents' DNA.

Key Vocabulary:

1. Offspring
2. DNA/RNA
3. Universal genetic code
4. Hereditary

(Video) DNA Spells Evolution

by NOVA PBS Official

Are all living things related? The answer is yes, and the evidence is DNA. This video explains how passing down DNA from generation to generation led to the multitude of species we have today.

Heritable Traits

Heredity is the passing of characteristics from one generation to another.

Organisms that reproduce through asexual methods end up having the same genetic features as their parents. They are pretty much clones of their parent. However, living things that reproduce through sexual methods get half of their DNA from each parent.

Organisms are able to pass on traits because they all share a genetic code. Inside every cell of every living thing, there is a hidden genetic code. In eukaryotes, this information is stored in the nucleus in chromosomes, which are just bundled up pieces of DNA.

DNA (or sometimes RNA) is known as the universal genetic code. These two types of nucleic acid are made of a few specific base pairs. The order of these base pairs is the "code" we are referring to, which is also called genes. Despite being made of the same base pairs, the ordering is what determines if something is a dog or a human.

$$\color{#8925AE}{\text{Vocabulary Review:}}$$

$\color{#8925AE}{\text{Cell}}$ : Smallest unit of life

$\color{#8925AE}{\text{Reproduction}}$ : Sexual reproduction is when two organisms combine their genetic information to create a unique offspring. Asexual is when one organism creates a copy of itself

$\color{#8925AE}{\text{Heredity}}$ : The genetic information inherited from the organism's parents

$\color{#8925AE}{\text{Development}}$ : How organisms grow and mature

Summary of Heredity

All living organisms must be able to reproduce and pass information to their offspring through genes.

• Genes are composed of deoxyribonucleic acid (DNA) and provide the information for the production of a new organism. This genetic makeup leads to observable traits.

• All living things share the same universal genetic code: DNA.

• The passing of genes to offspring causes the offspring to have traits similar to those of the parents. This is what causes children to look like their parents.

Scientists Who Observed Heredity

There are a few very important scientists who made use of this concept to explain how different traits get passed down and how evolution occurs.

• Gregor Mendel: He studied heritable traits in pea plants. Because of his work, we have an understanding of dominant and recessive traits, alleles, and variation among individuals.

• Jean-Baptiste Lamarck: He believed in the inheritance of acquired traits. This means that if an organism changes its body in some way, it will pass that change onto its offspring. Although this theory was later shown to be incorrect, he set out some great ideas for other scientists to build upon. He showed that the environment plays a role in development and that organisms do change over time.

• Charles Darwin: He came up with the theory of natural selection, which is the current theory of evolution.

Why Is DNA Considered the Universal Genetic Code?

DNA is considered a universal genetic code because every known living organism made of cells has genes consisting of DNA. Bacteria, fungi, cats, plants, and you: every organism uses DNA to store genetic information.

What Is DNA?

Just like how computers use 0's and 1's to code information that can become as complex as a video game, DNA is a simple system with four bases that can create very complicated products. The main four bases of DNA are adenine, tyrosine, cytosine, and guanine. You often see the bases referred to by their first letters: A, T, C, and G, respectively.

Every living organism uses a system where DNA is transcribed into RNA and then is translated into a protein product. Basically, every three pieces of DNA become one amino acid. The amino acid it becomes depends upon that three-letter sequence. Pretty much every organism uses the same translation system of DNA sequences to order amino acid chains. The exception is some bacteria, which have a few unique amino acids.

Since every living organism uses this system, it is considered to be a universal genetic code. And because all cells come from parent cells, cells are able to inherit DNA from their parent cells. This process is known as heredity. For example, if a dog has a thick fur coat and it has puppies that also have thick fur coats, then you know those puppies inherited DNA that coded for that type of fur.