Molecular genetics

Heizendorf, Austria

July 22nd, 1822

Botanist and Scientist

University of Vienna

University of Olmütz

Father of Modern GeneticsMonk of Agustinian order at St. Thomas Monastery, Brno

Chromosomes are made of very

tightly wound DNA (Deoxyribonucleic Acid). DNA carries

the genetic material for all living things.

Genes are portions of DNA.

Tsuneko and Reiji Okazaki studied theprocess of replication of DNA during celldivision. They complemented the descriptionof the process by describing the Okazakifragments.

Is the process in which DNA encodes to buildproteins.

Before the synthesis of a protein begins, the corresponding RNA (Ribonucleic Acid) molecule is produced by RNA transcription. One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize a messenger RNA (mRNA). This mRNA migrates from the nucleus to the cytoplasm.

During this step, mRNA goes through different types of maturation including one called splicing when the non-coding sequences are eliminated. The coding mRNA sequence can be described as a unit of three nucleotides called a codon.

The ribosome binds to the mRNA at the start codon (AUG) that is recognized only by the initiator tRNA. The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes, composed of an amino acid linked to tRNA, sequentially bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNAanticodon.

. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into polypeptidicsequences dictated by DNA and represented by mRNA. At the end, a release factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.

DNA GCT GCC GCA GCG

mRNA CGA CGG CGU CGC

tRNA GCU GCC GCA GCG

When a pair of bases is occasionallymismatched, and the repairing enzymesreplace the original nucleotide instead of themismatched.

One or more nucleotide pairs are insertedinto the DNA double helix.

One or more nucleotide pairs are removed from the double helix.

When a piece of DNA is cut out of a chromosome, turned around, and reinsertedinto the gap.

When a chunk of DNA, often very large, isremoved from one chromosome and attached to another one.

“The material of inheritance is carried by the genes in chromosomes”

Walter S. Sutton (American Biologist. 1903)

A chromosome has many genes. When genes for two traits are located in the same chromosome, the two genes travel together into the same gamete, so they are inherited together instead of sorting independently.

Chromosomes are divided into sex chromosomes (Those that define whether the offspring are male or female) and autosomes (non-sex chromosomes)

Humans and other mammals have two sex chromosomes. XX for females and XY for males.

Genes found only in the X chromosome are X-linked genes, and genes found only in the Y chromosome are Y-linked genes.

X and Y chromosomes are plenty different. They don’t recombine, so Y chromosome loses genes. X chromosome has the opportunity to show genes of the loosen parts of Y.

When X can show what it has…

In the retina there are twotypes of cells: rods and cones that enable vision. Cones are responsible forcolor vision. Sometimesthey undergo geneticalterations that make thesubject to perceive thecolors in a wrong way.

The loss of 70 to 90% of the hair without medical or stress reasons. Women rarely suffer baldness. They may experience diffuse thinning of their hair.

Genetic disorder that affects the ability of the body to control blood clotting or coagulation.

Refers to the loss of melanin from basal cells in the epidermis.

Typical neonatal rash

Typical hyperpigmentation

Linear, atrophic, hairless lesions.

We have the right quantity…

Turner syndrome is a genetic defect in which one of the two sex chromosomes is missing or defective. This disease affects 1 in 2500 live female births each year.

also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells.

High levels of testosterone.

Severe acne Over 6 feet tall.

It is in your DNA…

The lack of producing tyrosinase. The enzime to produce melanin. The dark pigment of the skin, iris and hair.

Mutation in the hemoglobin gene.

Red blood cells are weak and fragile.

Can cause anemia because many red blood cells are destroyed.

There are less oxygen in the blood.

Dominant disorder that causes a slow, progressive deterioration of parts of the brain after the 30 to 50 years.

Loose of coordination. Flailing movements. Personality

disturbances.

Extra copy of chromosome 21

Weak muscle tone Small mouth held

partially open Distinctively shaped

eyelids. Low resistance to

infectious diseases Heart malformations Varying degrees of

mental retardation

Mutations in the CFTR production (CFTR hormone helps reabsorbing salt avoiding dehydration of cells.)

Mucus in the lungs is dehydrated and thick.

Cilia can’t move and bacteria stay in the lungs.

Incapability to metabolize a lipid that stays in the brain causing blindness and brain damages.

Lack of the enzyme to break down the aminoacidphenylalanine.

Accumulations of phenylalanine can cause damage in nerve cells leading to severe developmental disabilities and death

Watch your actions…

Tobacco products are dangerous mutagens that may produce serious damage in DNA causing respiratory, cardiac, digestive or nervous system diseases.

Pregnant women who smoke can cause their babies growth and development problems, mental retardation, or even death because of spontaneous abortion.

Alcohol is an strong mutagen that can cause liver damages, brain diseases, bloodstream problems and so many other diseases.

Pregnant women can cause their babies Fetal alcohol syndrome that includes physical, mental and behavioral defects.

They act as mutagens that affect the nervous system, the endocrine and the cardiovascular system.

Pregnant women can cause serious damage to their babies as mental retardation, and other mental diseases, addiction and even malformations.

Psychotropic substances can cause abortions.

Radiation is a very dangerous mutagen that can cause translocations and other mutations in cell DNA.

A pregnant woman exposed to radiation can affect the baby in many ways: Malformations, mental retardation or death.

UV rays are harmful to the skin cells.

Cancer is uncontrolled, abnormal cell division.

There are many different forms of cancer as cells in our body.

Cancer cells can migrate from one part of an organism to another part.

Cancer can result of genetic or environmental factors.

Is a gene that causes a cell to become cancerous.

Some oncogenes in humans appear to be mutated forms of genes that code for proteins called growth factors that help cell division and differentiation.

Some others result from changes in the tumor suppressor genes.

A mutation can occur in a growth factor gene An error in DNA replication can result in

multiple copies of a single growth-factor gene.

A change in a gene’s location can create an oncogene (translocation)

Carcinogens as tobacco products, alcohol and some other drugs can replace or change DNA bases.

Have a diet low in fat and high in fiber and beta-carotene.

Have a diet rich in vitamins A, C, and E, and omega-3. Avoid burned foods.

Avoid smoking (even passive), alcohol and other drugs.

Protect yourself from the UV rays of the sun. Make exercise and remain calm and relaxed.

Stress is not good. Find out about your family history and talk to

your doctor.