Chromosome 4 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome….

A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins.

Each of the estimated 30,000 genes in the human genome makes an average of three proteins. What is a genome? A genome is an organism’s complete set of deoxyribonucleic acid (DNA), a chemical compound that contains the genetic instructions needed to develop and direct the activities of every organism.

Mosaic trisomy 4 is very rare; only a few cases have been reported. Other changes in the number or structure of chromosome 4 can have a variety of effects including delayed growth and development, intellectual disability, distinctive facial features, heart defects, and other medical problems.

The most common types of autosomal trisomy that survive to birth in humans are:

• Trisomy 21 (Down syndrome)
• Trisomy 18 (Edwards syndrome)
• Trisomy 13 (Patau syndrome)
• Trisomy 9.
• Trisomy 8 (Warkany syndrome 2)

What kinds of gene variants are possible?

• Missense. A missense variant is a type of substitution in which the nucleotide change results in the replacement of one protein building block (amino acid) with another in the protein made from the gene.
• Nonsense.
• Insertion.
• Deletion.
• Duplication.
• Frameshift.
• Repeat expansion.

There are three types of DNA Mutations: base substitutions, deletions and insertions. Single base substitutions are called point mutations, recall the point mutation Glu —–> Val which causes sickle-cell disease. Point mutations are the most common type of mutation and there are two types.

Silent mutations occur when the change of a single DNA nucleotide within a protein-coding portion of a gene does not affect the sequence of amino acids that make up the gene’s protein.

A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke. Mutations can occur during DNA replication if errors are made and not corrected in time.

Substances

• Carcinogens.
• Ethylene Dichlorides.
• Flame Retardants.
• Hair Dyes.
• Hydrocarbons, Halogenated.
• Mutagens.
• Furylfuramide.
• Ethylene Dibromide. DNA.

Chemical Mutagens change the sequence of bases in a DNA gene in a number of ways; mimic the correct nucleotide bases in a DNA molecule, but fail to base pair correctly during DNA replication. remove parts of the nucleotide (such as the amino group on adenine), again causing improper base pairing during DNA replication.

Most chemical mutagens are alkylating agents and azides. Physical mutagens include electromagnetic radiation, such as gamma rays, X rays, and UV light, and particle radiation, such as fast and thermal neutrons, beta and alpha particles.

Abstract. Alcohol is mutagenic, cancerogenic and teratogenic in man. Ethanol is mutagenic via its first metabolite, acetaldehyde. This is substantiated by the findings that acetaldehyde induces chromosomal aberrations, sister-chromatid exchanges and cross-links between DNA strands.

Alcohol can cause irreversible genetic damage to stem cells, says study. Alcohol can cause irreversible genetic damage to the body’s reserve of stem cells, according to a study that helps explain the link between drinking and cancer.

Coffee and caffeine are mutagenic to bacteria and fungi, and in high concentrations they are also mutagenic to mammalian cells in culture. However, the mutagenic effects of coffee disappear when bacteria or mammalian cells are cultured in the presence of liver extracts which contain detoxifying enzymes.

Such mutagens are called promutagens.

• Physical mutagens.
• DNA reactive chemicals.
• Base analogs.
• Intercalating agents.
• Metals.
• Biological agents.
• Bacterial.
• Yeast.

DNA changes caused by mutagens may harm cells and cause certain diseases, such as cancer. Examples of mutagens include radioactive substances, x-rays, ultraviolet radiation, and certain chemicals.

In genetics, mutagen induced changes are known as mutation. The mutations are categorized under two broader categories; gene mutations and chromosomal mutations. The present topic is very important, in order to understand the mechanism of how genetic mutations originate in nature.

EtBr is a potent mutagen (can cause genetic damage), and moderately toxic after an acute exposure. EtBr can be absorbed through skin, so it is important to avoid any direct contact with the chemical. The powder form is considered an irritant to the upper respiratory tract, eyes, and skin.