Inheritance

Gregor Mendel

conducted experiments with Pisum Sativum (garden pea) Cross Pure bred with plants of contrasting traits eg yellow seed crossed with green seed

Factors which determines a inherited characteristic

Alternative form of a gene

Always expressed if present , has the ability to mask effects of other alleles

Expressed in absence of a dominant allele, usual masked by a dominant allele represented in Lowercase

Both alleles of a particular characteristic are the same

Both alleles of a particular characteristic is different

Only having half of the alleles, usual always in males due to having 1 x chromosome

Physical characteristic/appearance that is determined by the alleles expressed

a sample of the DNA is cut at particular base sequences and placed on a bed of gel. Electrophoresis results in the pieces of DNA forming a banding pattern dependent on the size of the DNA fragment. This banded picture is the person’s DNA profile or fingerprint.

Can help detect/trace hereditary diseases at an early age = better chance to get treated Identify alleles that have mutated

Offspring

Two affected parents producing a UNaffected child

Two UNaffected parents producing a Affected child

Fathers with affected trait passes it onto ALL of their daughters as their Y chromosome is passed down to their sons

Mothers with affected trait passing it onto ALL of their sons

The trait for a allele is segregated/separated during formation of gametes

Advice given to parents or couple about to the risk that an inherited condition may be passed onto their offspring. Making them have an informed decision about if they wish to have a child or not

inherited characteristics are controlled by genes, and that each gamete receives one set of genes.

Autosomal Dominant Characterised by occasional involuntary flailing movements of the arms and legs. In addition, the person often has difficulty making voluntary movements of the limbs

Autosomal Recessive controls the production of an enzyme called phenylalanine hydroxylase (This enzyme converts the amino acid phenylalanine to tyrosine) If not present, then phenylalanine will accumulate in the bloodstream and become toxic

Autosomal Recessive Children with the condition suffer from chest infections, lack of digestive enzymes and increased salt loss

a blood sample is usually taken from the baby’s heel within two to three days after birth. IS given a special diet low in fat and high in carbohydrate and protein