How does genotype become phenotype




















Genotype and phenotype are clearly discrete ideas, but they are often mentioned in tandem. This is complicated, because our traits result from combinations of genes. There is rarely a trait that is linked to only one specific gene.

Specifically, researchers want to know not only which genes are involved, but which variations within those genes are associated with a particular trait. For example, researchers have determined that the BRCA1 gene is linked to breast cancer risk in humans. But simply having this gene does not tell us much, because only specific variations of BRCA1 have been associated with increased risk. Which genes put humans at risk of diabetes?

In rice species, which genes make a plant susceptible to common diseases? This has provided a lot of information about genes and genomes and made it possible to investigate the relationship between genotype and phenotype. Researchers are finding that there are more similarities between genomes of different organisms than there are differences and that many of the phenotypic differences between organisms are due to differences in the way their genes are turned on and off, not due to what genes they have.

Evolution and development are particular themes for the research carried out by Peter and his colleagues. Current work focuses on investigating how the processes that occur during the development of an organism change over evolutionary time scales to give different forms of the same organism. To carry out this research, Peter and his colleagues work with a number of model organisms, including honey bees Apis mellifera and fruit flies Drosophila melanogaster. Animal and cell-based models are often needed to explore the complexity of human development and genetics.

The biological pathways between animal models and humans are not identical, but discoveries made using a model organism often allow scientists to gain a better understanding of human development and disease.

The particular line of scientific inquiry will inform the animal model the scientist chooses. However, this type of research is very challenging! Yet other proteins are structural, i. A slight difference in the DNA sequence will have an effect on the sequence of RNA and the sequence of the resulting protein, affecting the primary, secondary and tertiary structure of that protein.

The changes in 3D shape of the protein will affect its efficiency in performing its function. For instance, if two proteins interact with each other, and in order to do so need to bind each other, and they bind because their shapes fit into each other like lock and key, then change of shape of one protein is going to alter the efficiency of binding of the two.

Changes in shapes of both proteins can either slow down or speed up the reaction. Change of rate of that one reaction in the cell will have effects on some other reaction in the cell, including the way the cell reacts to the signals from the outside.

Thus genes, proteins, other chemicals inside the cell, inter-cellular interactions and the external environment ALL affect the trait.

Most importantly, as the traits are built during development, it is the interactions between all these players at all levels of organizations during development that determine the final phenotype of the organism. The importance of the environment can be seen from the phenomenon of the norm of reaction.

The same genotype, when raised in different environments results in different phenotypes. Furthermore, different genotypes respond to the same environmental changes differently from each other.

One genotype may produce a taller plant at higher elevation while a slightly different genotype may respond quite the opposite: producing a shorter plant at higher elevations. I have given you handouts see below with four different alternative metaphors, at least one of which, I hope, will feel clear and memorable to each student. I will now give you a fifth such metaphor, one of my own:. Imagine that a cell is an airplane factory. It buys raw materials and sells finished airplanes.

How does it do so? The proteins are the factory workers. Some of them import the materials, others are involved in the sale of airplanes. Some guard the factory from thieves, while others cook and serve food in the factory cafeteria. But the most important proteins of this cell are those that assemble the parts of airplanes. When they need a part, e. Other proteins storeroom managers go inside and find the correct part and send it to the assembly floor endoplasmic reticulum.

But, protein workers are themselves robots assembled out of parts right there in the same factory, and the instructions for their assembly are also in the Catalogue of Parts DNA in the nucleus. How do you wear your genes?

Overall, the amount of influence that environmental factors have on your ultimate phenotype is a hotly debated scientific issue. In conclusion, your genotype or genetic make-up plays a critical role in your development. However, environmental factors influence our phenotypes throughout our lives, and it is this on-going interplay between genetics and environment that makes us all unique.

Add to collection. Genotype Genotype is the genetic make-up of an individual organism. Phenotype Phenotype is the observable physical or biochemical characteristics of an individual organism, determined by both genetic make-up and environmental influences, for example, height, weight and skin colour. Go to full glossary Add 0 items to collection. Download 0 items. Twitter Pinterest Facebook Instagram.



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