Variation and inheritance

Discrete and continuous VariationDifferences that can be seen between individual members of a species are called variation.Discrete - The differences are clear-cut and show a discontinuous pattern. E.g tongue rolling someone can either do it or not it is clear cutContinuous - There is a range of variation between extremes. The characteristic is polygenic (there is many different genes involved). Most features of an individual's phenotype (the visible characteristics) e.g height which shows a range as some people are tall and someone people are small. 

What is a gene?A gene is single piece of genetic information made from DNA. It carries the information to create a particular characteristic. Genes exist in different forms called alleles. Alleles - a form of geneAlleles are given symbols usually letters to make working with easier.Homozygous - has two alleles the sameHeterozygous - two alleles are different Genotype - the alleles an organism has for a particular characteristic usually written as symbols.

Dominant - Form of a gene they always show up in the phenotype of a plant. Have a capital letter.Recessive - Alleles only show up is they have two copies 

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