Download 2.3 Cell Continuity & Mitosis

Genetic Inheritance
• Genetics is the study of inheritance.
• In terms of agriculture, genetics is everything.
• An understanding of genetics is critical in breeding
strategies in any animal enterprise and in
producing new strains of barley, wheat, potatoes
etc.
• Most of what we know about genetics was
obtained from the work of an Austrian monk
called Gregor Mendel.
• He used pea plants to study how characteristics
were passed from one generation to the next.
• Pea plants grow quickly and are self pollinating
The genotype is the set of genes an individual
possesses.
Dominant genes are genes that are always expressed
when present.
Recessive genes are genes that are only expressed in
the absence of a dominant genes.
The phenotype is the physical effect produced by the
gene.
• Mendel studied traits that were clearly
dominant or recessive
• In incomplete dominance, no allele is
dominant and the offspring produce traits that
are “in-between”.
• For example, in Snapdragons, when red
flowers (PP) and white flowers (pp) cross
pollinate (cross fertilise), the offspring (Pp) will
produce pink flowers.
• Heterozygous plants, when cross-fertilised
with another heterozygous, will produce red,
pink and white flowers.