Genetic Conditions and Inheritance
Introduction[edit | edit source]
Genetic conditions are diseases or disabilities that are caused by inherited or aquired abnormalities in the sequencing of the genome.
Heredity or genetic inheritance is the process of passing off trades or characteristics from parents to their offspring, also referred to as the study of genetics.[1] Traits get inherited through genes. These are sections of the desoxyribonucleic acid (DNA) molecule which hold all information needed to for an organisms to build new cells.
History[edit | edit source]
Gregor Mendel (1822-1884) was a scientist and monk from the Austrian Empire (today's Czech Republic) and is referred to as "the founder of the science of modern genetics".[2] His scientific experiments, which he conducted during his life in the monastery using pea plants, led him to construct the theory of inheritance of trades. Mendel was the first person to identify and prove the correct hypothesis of genetic inheritance of characteristics through "recessive" and "dominant" trades, which are both terms that he coined. He published his findings in 1865 but only gained posthumous recognition for the relevance of his work.
Genetic inheritance / Heredity[edit | edit source]
This capter will capture the basics about inheritance. For a great visualisation about this topic see the YouTube video by the Crash Course brothers below.
Definitions[edit | edit source]
Traits[edit | edit source]
Traits - or characteristics - are observable details of an organism, e.g. in humans: one's eye colour, the shape of one's finger nails, ...
- Mendelian trait: A characteristic or trait that is determined by one gene only.[3] This means that a specific characteristic's information is found on only one of the 23 chromosome pairs that a human DNA. Therefore, the information about this particular characteristic is linked to one specific location within the DNA. The typical example is the colour of pea plant flowers, which was the trait that Mendel examined in his experiments.
- Poligenic trait: A characteristic or trait that is a composition of information from different genes, ergo not tied to one single location within the DNA. Most traits, since they are quite elaborate, are poligenic traits.
- Pleiotropic: A gene that influences how other genes are interpreted.
To best comprehend the pathway of genetic inheritance most commonly examples of Mendelian traits are used, since the observed trait is determined by one single gene.
Chromosomes[edit | edit source]
Chromosomes are the strings made of the double helix DNA. In the human body they come in pairs. Humans have 23 pairs of chromosomes.
Genes[edit | edit source]
Alleles[edit | edit source]
Genotype[edit | edit source]
The genotype is the composition of the two parentally inherited alleles. [1]
- Heterozygous: Genotype has two alleles that are different.
- Homozygous: Genotype has two alleles that are alike.
Phenotype[edit | edit source]
The phenotype is defined as "the set of characteristics of a living thing, resulting from its combination of genes and the effect of its environment"[4] hence the 'final result' of the composition of parentally inherited and environmentally aquired information.
Genetic inheritance pathways[edit | edit source]
The Punnet Square[edit | edit source]
Diagnosis[edit | edit source]
Clinical relevance[edit | edit source]
Most common disorders[edit | edit source]
- Haemophilia
- Von Willebrand Disease (specific form of haemophilia)
- Thalassaemia
- Sickle Cell Anaemia
Most common disorders in physiotherapy practice[edit | edit source]
Treatment[edit | edit source]
Experimental genometherapy[edit | edit source]
Physiotherapy[edit | edit source]
References[edit | edit source]
- ↑ 1.0 1.1 Genetic inheritance. Basic Biology 2020. Available from: https://basicbiology.net/micro/genetics/genetic-inheritance (accessed 3 November 2020).
- ↑ Gregor Mendel. Wikipedia. Available from: https://en.wikipedia.org/wiki/Gregor_Mendel (accessed 3 November 2020).
- ↑ Heredity: Crash Course Biology #9. Crash Course (YouTube Channel). Available from: https://www.youtube.com/watch?v=CBezq1fFUEA (accessed 3 November 2020).
- ↑ Phenotype. Oxford Learner's Dictionaries. Available from: https://www.oxfordlearnersdictionaries.com/definition/english/phenotype?q=phenotype (accessed 3 November 2020).
