Patterns Of Inheritance Flashcards
Define Gene
A sequence of bases on a DNA molecule that codes for sequence of amino acid in a polypeptide chain
Define allele
Different form of a gene
Define phenotype
Observable traits of an organism that is caused by the expression of the allele in the genotype and the environment
Define recessive
Only expressed when there are two allele coding for a recessive feature in a homologous genotype with the absense of a dominant allele
Define dominant
Allele that is always expressed whether it is hetereozygous or homozygous only one allele is needed for the phenotype to be expressed
Imcomplete dominane
Where two allele of a gene both contribute to the phenotype
Heterozygote
When the genotype has two different alleles
Homozygote
When the genotype has two of the same allele
Define codominane
In heterozygotes, where both alleles at a gene locus are fully expressed in the phenotype
Haemophilia
Siamese cats and other rabbit breeds
Genotype suggest that they should have dark fur all over their body (due to melanin produced in the process involving tyrosine enzyme)
However a mutation occurring in the genes of Siamese cat result in inactivation of tyrosinase enzyme at normal temperature
At normal temperature enzyme tyrosine is inactivated - > pale body colour
Dark extremities
(Nose,paws,ears and tail) since lower temperature
Are darker due to being away from centre of the body the temp is lowered the enzyme is not denatured and as a result the fur is dark
Continuous variation height
Height has both genetic and environment element
If an individual hasa balanced diet throughout the growing years then more likely to achieve their genetic height potential
But if they are malnourished they can’t grow to their potential height due to
- protein is required for growth
- calcium ions needed for bone growth
If someone has a shortness gene they will not become no matter what
