Some types of cancer are triggered by environmental factors such as diet and lifestyle. For example, prolonged exposure to the sun is linked to melanoma. Avoiding such triggers means significantly reducing the risks. Related parents are more likely than unrelated parents to have children with health problems or genetic conditions. This is because the two parents share one or more common ancestors and so carry some of the same genetic material.
If both partners carry the same inherited gene change, their children are more likely to have a genetic condition. Related couples are recommended to seek advice from a clinical genetics service if their family has a history of a genetic condition. If a family member has been diagnosed with a genetic condition, or if you know that a genetic condition runs in your family, it can be helpful to speak to a genetic counsellor.
Genetic counsellors are health professionals qualified in both counselling and genetics. As well as providing emotional support, they can help you to understand a genetic condition and what causes it, how it is inherited if it is , and what a diagnosis means for you and your family.
Genetic counsellors are trained to provide information and support that is sensitive to your family circumstances, culture and beliefs. Genetic services in Victoria provide genetic consultation, counselling, testing and diagnostic services for children, adults, families, and prospective parents. They also provide referral to community resources, including support groups, if needed. This page has been produced in consultation with and approved by:. The characteristic features of Angelman syndrome are not always obvious at birth, but develop during childhood.
Latest research suggests that most cancers are caused by environmental rather than genetic factors. Folic acid taken before conception, and during at least the first four weeks of pregnancy, can prevent around seven out of 10 cases of neural tube defects.
Charcot-Marie-Tooth disease is the most common inherited disorder affecting the peripheral nervous system. Most cleft palates and cleft lips can be repaired so that appearance and speech develop normally. Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional.
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The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. Skip to main content. Genetic conditions.
Home Genetic conditions. Genes and genetics explained. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. Chromosomes How we inherit characteristics Dominant and recessive genes Co-dominant genes Gene changes in cells Genetic conditions Genes and genetics — related parents Genetic counselling and testing Where to get help.
Chromosomes Humans typically have 46 chromosomes in each cell of their body, made up of 22 paired chromosomes and two sex chromosomes. How we inherit characteristics Parents pass on traits or characteristics, such as eye colour and blood type, to their children through their genes.
Examples of inheritance patterns include: autosomal dominant — where the gene for a trait or condition is dominant, and is on a non-sex chromosome autosomal recessive — where the gene for a trait or condition is recessive, and is on a non-sex chromosome X-linked dominant — where the gene for a trait or condition is dominant, and is on the X-chromosome X-linked recessive — where the gene for a trait or condition is recessive, and is on the X-chromosome Y-linked — where the gene for a trait or condition is on the Y-chromosome co-dominant — where each allele in a gene pair carries equal weight and produces a combined physical characteristic mitochondrial — where the gene for a trait or condition is in your mitochondrial DNA, which sits in the mitochondria powerhouse of your cells.
Eye colour The allele for brown eyes B is dominant over the allele for blue eyes b. Blood groups For blood groups, the alleles are A, B and O. Basic genetics , Learn. Give feedback about this page. The egg and sperm each have one half of a set of chromosomes. The egg and sperm together give the baby the full set of chromosomes. A genetic disorder happens when a gene or genes has a problem with its code, and this causes a health problem.
Sometimes a genetic disorder happens when a child inherits it from one or both parents. Other times, it happens only in the child and the parents do not have the genetic disorder.
Scientists are learning more and more about genetics. A worldwide research project called The Human Genome Project created a map of all human genes. It shows where the genes are located on the chromosomes. Doctors can use this map to find and treat or cure some kinds of genetic disorders. There is hope that treatments for many genetic disorders will be developed in the future. Reviewed by: Amy W. They give instructions for a living being to make molecules called proteins.
A geneticist is a person who studies genes and how they can be targeted to improve aspects of life. Genetic engineering can provide a range of benefits for people, for example, increasing the productivity of food plants or preventing diseases in humans.
Genes are a section of DNA that are in charge of different functions like making proteins. Long strands of DNA with lots of genes make up chromosomes.
DNA molecules are found in chromosomes. Chromosomes are located inside of the nucleus of cells. Each chromosome is one long single molecule of DNA. This DNA contains important genetic information. Chromosomes have a unique structure, which helps to keep the DNA tightly wrapped around the proteins called histones. If the DNA molecules were not bound by the histones, they would be too long to fit inside of the cell.
Genes vary in complexity. In humans, they range in size from a few hundred DNA bases to more than 2 million bases. Different living things have different shapes and numbers of chromosomes. Humans have 23 pairs of chromosomes, or a total of A donkey has 31 pairs of chromosomes, a hedgehog has 44, and a fruit fly has just 4. DNA is passed from adult organisms to their offspring during reproduction.
The building blocks of DNA are called nucleotides. Nucleotides have three parts: A phosphate group, a sugar group and one of four types of nitrogen bases. A gene consists of a long combination of four different nucleotide bases, or chemicals. There are many possible combinations. Different combinations of the letters ACGT give people different characteristics. Genes carry the codes ACGT. Each person has thousands of genes.
They are like a computer program, and they make the individual what they are. A gene is a tiny section of a long DNA double helix molecule, which consists of a linear sequence of base pairs. A gene is any section along the DNA with instructions encoded that allow a cell to produce a specific product — usually a protein, such as an enzyme — that triggers one precise action.
DNA is the chemical that appears in strands. This is what makes each person unique. DNA is made up of two long-paired strands spiraled into the famous double helix. Each strand contains millions of chemical building blocks called bases. Genes decide almost everything about a living being.
One or more genes can affect a specific trait. Genes affect hundreds of internal and external factors, such as whether a person will get a particular color of eyes or what diseases they may develop. A gene is a basic unit of heredity in a living organism. Genes come from our parents. We may inherit our physical traits and the likelihood of getting certain diseases and conditions from a parent. Genes contain the data needed to build and maintain cells and pass genetic information to offspring.
Each cell contains two sets of chromosomes: One set comes from the mother and the other comes from the father. The male sperm and the female egg carry a single set of 23 chromosomes each, including 22 autosomes plus an X or Y sex chromosome.
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