Note that your final mark will not be saved in the system.
Inheritance and variation Typeit
Type the correct answers into the spaces. Fill all the spaces before clicking ‘Check Answers!’
Some genes have alternative versions called in which a has taken place to change it slightly, so the phenotype displayed is not always the same.
We can predict the outcomes of single gene crosses using squares if we know the genotypes of the parents, i.e. whether they are homozygous or for a trait. For example, cystic fibrosis is a condition that is only caused by inheriting two alleles. However, most characteristics are a result of multiple interacting so it is not easy to predict an offspring's phenotype.
Some genetic disorders are referred to as -linked because the gene responsible is found on either the X or Y chromosome. For example, in red-green colour , males inheriting an affected X chromosome will always have the disorder, whereas females are less often affected because they will usually also have a , unaffected allele on their second X chromosome.
Some traits are caused by alleles which show , i.e. multiple different versions of a gene can affect the result. An example of this is shown by the inheritance of types - there are three alleles involved, one of which is recessive to the other two. The four resulting types are A, B, O and .