Slides in this set
What is an allele?
· An allele is something which is coded for the
same gene or characteristic, but is a different
version of that gene.
· Most genes have more than one type.
· For example, eye colour. People have
different eye colours, such as green, brown,
grey and blue. These different eye colours
are different alleles of the same gene.…read more
What is dominant and
· Dominant alleles are always expressed if present. This
includes brown hair and brown eyes, and also faulty genes
like the gene for Huntington's disease. If a parent passes on
one of these alleles to their child, then this will be the allele
which is expressed regardless of the other parent's allele.
· Recessive alleles can only be expressed if both parents
pass on the same allele. So only a recessive allele can be
present for it to show. This includes ginger hair, blue eyes
and the faulty gene for cystic fibrosis. These will only be
expressed when they are the only form of the gene present
in an offspring's genetics.…read more