Genetic Vocabulary

Allele – one form of a gene (1 trait). Ex. Hair Color

Dominant – Allele (trait) that shows physically in the offspring. Dominant Alleles are represented with a capital letter. Ex. A = Black Hair

Recessive – Allele (Trait) that does NOT show physically in the offspring. Recessive Alleles are represented with a lower case letter. a = Blonde Hair

DNA – Information passed on through cell reproduction. DNA makes up genes. EX.

Gene – Carries the information about heredity in the sperm (male) and egg (female). Ex.

Chromosomes – Genes strung together to make a ladder chain.

Genotype – refers to the gene that is used for a particular trait. Ex. AA, Aa, aa

Phenotype – refers to the trait or characteristic that is used in a particular gene. Ex. Black hair, Brown hair or Blonde Hair.

Heredity – passing down of mental and physical traits (characteristics) from parents to their children. Ex. Grandchild has grandpa’s dimples.

Heterozygote – Offspring that has two different alleles for a given trait. This is also known as a HYBRID. Ex. Aa

Homozygote – Offspring that has two identical alleles for a given trait. Dominate is known as PRUEBREED, Recessive is known as RARE. Ex. AA or aa

Offspring – Descendants that are born from sexual reproduction in a certain line of genetics. Ex. Kitties, puppies, babies, & other animals.

Sexual Reproduction – Sperm and Egg create a genetically unique offspring from two parents.

Asexual Reproduction – One parent creates a genetically identical offspring from itself.

Gregor Mendel – Monk scientist that discovered passing of DNA in sexual reproduction.

Genetic Predictions

  1. In daisies, the yellow petal is dominant over the white. If a homozygous dominant (AA) and heterozygous (Aa) daisy crossed pollenated… A A

_____ How many would be homozygous dominant? A

_____ How many would be heterozygous?AAAA

_____ How many would be white? a

_____ How many would be yellow?AaAa

  1. Curly hair is dominant over straight hair. Cross a male who is heterozygous (Aa) for curly hair with a female who is homozygous recessive (aa) for straight hair.

_____ How many offspring would be homozygous recessive?

_____ How many would be heterozygous?

_____ How many would have curly hair?

_____ How many would have straight hair?

  1. In frogs, dark green spots are dominant over yellow. What would be the results of two hybrid (Aa) parents?

_____ How many of the offspring would be homozygous dominant?

_____ How many would be heterozygous?

_____ How many would have green spots?

_____ How many would have yellow spots?

  1. Horned cattle are dominant to hornless cattle. Use a Punnett Square to show the expected offspring form the mating of a heterozygous horned bull (Aa) with a homozygous recessive (aa) hornless cow.

_____ Horned?_____ Hornless?_____ Heterozygous? _____ Homozygous recessive?

_____ Homozygous dominant?______Possible Genotypes?

______Possible Phenotypes?

  1. Sickle Cell Anemia is a recessive trait. In families where both parents have the heterozygous sickle cell trait, how many of the offspring would you expect?

_____ Normal?_____Sickle Cell Anemia?_____ Carrier?

_____ Homozygous dominant? _____ Homozygousrecessive?

______Possible Genotypes?______Possible Phenotypes?