Genes and Traits

Genes and traits

• Genes determine traits.• Genes usually occur in pairs.• Therefore there are usually 2

genes for a trait or characteristic.

Term to Remember

•Allele- each form of a gene.

•For eye color there are several alleles- blue, brown, green,

Symbols• The dominant gene or allele gets a capital

letter

• The recessive gene or allele gets a lower case of the same letter.

Review

• How many genes for a trait?

• 2

• The dominant allele is represented by

• Capital letter

Ear lobes

• The way your ear lobe is attached to your head is an inherited characteristic.

• Free ear lobes are dominate

• Attached ear lobes are recessive

• Symbol for Free earlobes= F

• Symbol for attached earlobes = f

What do earlobes look like?

Review

• Someone who is FF: what type of earlobes will they have?

• Free

Review

• Someone who is Ff: what type of earlobes will they have?

• Free

Review

• Someone who is ff: what type of earlobes will they have?

• attached

Terms to Remember

• Genotype: the actual two genes the person has inherited.

• FF

• Ff

• ff

Terms to Remember

• Phenotype: the physical expression of the genes, what we can see or is expressed by the gene combination.

• Free earlobes or attached earlobes

Terms to Remember

• Pure bred: the two genes or alleles for the trait are the same, two dominant or two recessive

• Hybrid: one dominant and one recessive allele for a trait.