How much genetic variation is there

Like a recipe book it holds the instructions for making all the proteins in our bodies. Genes are small sections of DNA within the genome that code for proteins. They contain the instructions for our individual characteristics — like eye and hair colour. Inheritance is the process by which genetic information is passed on from parent to child. This is why members of the same family tend to have similar characteristics.

In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. 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. If you have any other comments or suggestions, please let us know at comment yourgenome.

Can you spare minutes to tell us what you think of this website? Open survey. Genetic variation in a population is derived from a wide assortment of genes and alleles. The persistence of populations over time through changing environments depends on their capacity to adapt to shifting external conditions.

Sometimes the addition of a new allele to a population makes it more able to survive; sometimes the addition of a new allele to a population makes it less able. Still other times, the addition of a new allele to a population has no effect at all, yet the new allele will persist over generations because its contribution to survival is neutral.

Key Questions How can genetic variation influence evolution? What is an example of genetic drift? Topic rooms within Genetics Close. No topic rooms are there. Browse Visually. Other Topic Rooms Genetics. Student Voices. Creature Cast. Simply Science. Green Screen. Green Science. Bio 2. The Success Code. Why Science Matters. The Beyond.

Plant ChemCast. Postcards from the Universe. First, compared with many other mammalian species, humans are genetically far less diverse — a counterintuitive finding, given our large population and worldwide distribution. For example, the subspecies of the chimpanzee that lives just in central Africa, Pan troglodytes troglodytes , has higher levels of diversity than do humans globally, and the genetic differentiation between the western P.

Early studies of human diversity showed that most genetic diversity was found between individuals rather than between populations or continents and that variation in human diversity is best described by geographic gradients, or clines.

A wide-ranging study published in found that These results show that when individuals are sampled from around the globe, the pattern seen is not a matter of discrete clusters — but rather gradients in genetic variation gradual geographic variations in allele frequencies that extend over the entire world. The genes that are encoded within these proteins are what enable cells to function. Most organisms that reproduce sexually have two copies of each gene , because each parent cell or organism donates a single copy of its genes to its offspring.

Additionally, genes can exist in slightly different forms, called alleles, which further adds to genetic variation. The combination of alleles of a gene that an individual receives from both parents determines what biologists call the genotype for a particular trait, such as hair texture.

The genotype that an individual possesses for a trait, in turn, determines the phenotype —the observable characteristics—such as whether that individual actually ends up with straight, wavy, or curly hair. Genetic variation within a species can result from a few different sources. Mutations, the changes in the sequences of genes in DNA , are one source of genetic variation. Another source is gene flow , or the movement of genes between different groups of organisms.

Finally, genetic variation can be a result of sexual reproduction , which leads to the creation of new combinations of genes. Genetic variation in a group of organisms enables some organisms to survive better than others in the environment in which they live.

Organisms of even a small population can differ strikingly in terms of how well suited they are for life in a certain environment. An example would be moths of the same species with different color wings. Moths with wings similar to the color of tree bark are better able to camouflage themselves than moths of a different color. As a result, the tree-colored moths are more likely to survive, reproduce, and pass on their genes.