50 Photos Of Unique People That Show That Genetics Is Hard To Predict (New Pics)

Genes are hereditary information units that organisms pass down to new generations. Genes contain coded information for the production of proteins that enable cells to function. An organism’s entire collection of genes is called its genome.

The human genome, for example, contains somewhere between 20,000 and 25,000 genes. We resemble the people in our family because our genes are more similar to their genes than they are to those of strangers.

On the other hand, your genes are more similar to the genes of all other humans than they are to the genes of a different kind of organism, such as a rabbit. That being said, humans resemble chimpanzees because we share nearly 99 percent of the same genes.

Heredity is a concept that humans have been aware of for thousands of years as we’ve cultivated crops and selectively bred animals.

However, the first formal genetic study was undertaken by a monk named Gregor Mendel in the middle of the 19th century—Mendel bred peas and noticed he could cross-pollinate them in certain ways to get green or yellow seeds.

Nowadays, the field of genetics is breaking new ground searching for new ways to treat disease or develop crops more resistant to insects or drought.

While genomes may differ greatly, the genes themselves are all built in the same way. A gene is a section of a long molecule called deoxyribonucleic acid (DNA), or—in some viruses—a similar molecule called ribonucleic acid (RNA).

DNA and RNA are made of building blocks called nucleotides. Each nucleotide is constructed around one of the four different subunits, called bases. These bases are known as guanine, cytosine, adenine, and thymine (in RNA thymine is replaced with uracil).

A gene carries information in the sequence of its nucleotides, just as a sentence carries information in the sequence of its letters. Although most genes are made of DNA, the genes use RNA to make the proteins that are coded for in the DNA.

Genes are located on threadlike structures called chromosomes in the cell nucleus (a chromosome itself is a long molecule of DNA with proteins attached). Each cell of an organism carries at least one chromosome. Many organisms, including humans, have numerous chromosomes in their cells.

To make a protein from a gene in DNA, a cell first builds a strand of RNA that copies the information from the DNA molecule. This process is called the transcription of a gene.

The cell then uses the message in the RNA strand to build a protein molecule. This process is called the translation of a gene.

Only about one percent of our DNA is in protein-coding genes. The other 99 percent is noncoding DNA. Geneticists do not know the purpose of all this noncoding DNA, but they believe at least some of it is necessary for the proper functioning of cells, especially in controlling gene functions.