For example, if both of your parents have green eyes, you might inherit the trait for green eyes from them. Or if your mom has freckles, you might have freckles too because you inherited the trait for freckles. Genes aren’t just found in humans — all animals and plants have genes, too.

Many genes provide instructions for building polypeptides. How, exactly, does DNA direct the construction of a polypeptide? This process involves two major steps: transcription and translation. In transcription, the DNA sequence of a gene is copied to make an RNA molecule.

It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression. During the process of transcription, the information stored in a gene’s DNA is passed to a similar molecule called RNA (ribonucleic acid) in the cell nucleus.

Each chromosome contains hundreds to thousands of genes, which carry the instructions for making proteins. Each of the estimated 30,000 genes in the human genome makes an average of three proteins.

The chemicals come in four types A, C, T and G. A gene is a section of DNA made up of a sequence of As, Cs, Ts and Gs. Your genes are so tiny you have around 20,000 of them inside every cell in your body! Human genes vary in size from a few hundred bases to over a million bases.

Seventeen years after the initial publicationx of the human genome, we still haven’t found all of our genes. The answer turns out to be more complex than anyone had imagined when the Human Genome Project began.

According Kerpedjiev, the top-10 most-studied genes are:

• TP53;
• TNF;
• EGFR;
• VEGFA;
• APOE;
• IL6;
• TGFBI;
• MTHFR;

The four types of nitrogen bases found in nucleotides are: adenine (A), thymine (T), guanine (G) and cytosine (C). The order, or sequence, of these bases determines what biological instructions are contained in a strand of DNA.

Given that DNA molecules are found inside the cells, they are too small to be seen with the naked eye. While it is possible to see the (containing DNA) using a light microscope, DNA strands/threads can only be viewed using microscopes that allow for higher resolution.

deoxyribonucleic acid

What makes each person unique? The answer is DNA or deoxyribonucleic acid. DNA is a special molecule that tells your cells what to do. Inside cells are tiny structures called chromosomes and inside every chromosome are hundreds of genes.

The largest chromosome, chromosome 1, contains about 8000 genes. The smallest chromosome, chromosome 21, contains about 300 genes. The DNA that contains your genes is stored in your cells in a structure called the nucleus.

chromosome 1

Humans have 23 pairs of chromosomes–22 pairs of numbered chromosomes, called autosomes, and one pair of sex chromosomes, X and Y. Each parent contributes one chromosome to each pair so that offspring get half of their chromosomes from their mother and half from their father.

Y chromosome

Scientists estimate that the human genome, for example, has about 20,000 to 25,000 protein-coding genes….How Many Protein-Coding Genes Are in That Genome?

A microscopic, see-through water flea is the most complex creature ever studied, genomically speaking. Daphnia pulex is the first crustacean to ever have its genome sequenced, and it turns out it has about 31,000 genes — 25 percent more than we humans.

Table 1.

Since the onion (Allium cepa) is a diploid organism having a haploid genome size of 15.9 Gb, it has 4.9x as much DNA as does a human genome (3.2 Gb).