Introduction to Genetics
Jayne Bailes
Genotype
Gene Combination (at least two letters)
- Dimples are dominant (DD) while no dimples are recessive (dd).
- Curly hair is dominant (HH) while straight hair is recessive (hh).
Phenotype
Physical Appearance (tall, short, round)
- Freckles are recessive (ff) while no freckles are dominant (FF).
- Brown eyes are dominant (EE) while blue eyes are recessive (ee).
Homozygous
The two alleles (genes) for a trait are the same
- Tall pea plants are dominant (TT) to short pea plants (tt).
- Yellow seeds are dominant (YY) to green seeds (yy).
Heterozygous
The two alleles (genes) for a trait are different
- Dimples are dominant (Dd) while no dimples are recessive.
- Curly hair is dominant (Hh) while straight hair is recessive
Homozygous and Heterozygous
Dominant
The allele that masks or hides the recessive allele. (uppercase letter)
- Dd
- TT
- Ee
Recessive
The allele that is masked or hidden by the dominant allele. (lowercase letter)
- dd
- Tt
- rr
How can someone predict the traits of offspring?
You can predict the traits of offspring by knowing the dominant traits and recessive traits and putting them in a punnet square to know the chances of what traits the offspring will have.
Why is it important to study the principles of inheritance?
It's important to know how traits are passed to offspring because you can better understand why there is variation in offspring.