Practice - Inheritance Worksheet

Practice - Inheritance Worksheet

Directions: Answer the questions below about inheritance. This worksheet will cover all 3 types of inheritance we have learned, autosomal recessive, autosomal dominant, and X-linked recessive.

1. Freckles are an autosomal (non-sex-chromosomes) recessive trait. Cross a homozygous dominant man with a homozygous recessive woman.

% children with freckles______

2. Dimples are an autosomal dominant trait in humans. Cross a homozygous dominant man with a homozygous recessive woman.

% children with dimples______

3. In flies, white eyes are an X-linked recessive trait. Cross a carrier female with a red-eyed male fly. What % of the children would have white eyes? What % of the girls would be carriers? What percent of all the kids would be carriers?

% white-eyed children______

% carrier girls______

% carrier children______

4. In the alien species of Oggs, the number of feet is an autosomal dominant trait. Homozygous dominant Oggs have 2 feet. Heterozygous Oggs (carriers) have 1 foot and homozygous recessive Oggs have 0 feet. Cross a 1 footed female Ogg with a 2 footed male Ogg. What is the genotypic ratio? Phenotypic ratio?

Genotypic ratio______

Phenotypic ratio______

5. Oggs can have up to 3 eyes. The number of eyes is an X-linked trait. Oggs showing the recessive phenotype have 3 eyes. Oggs with the dominant phenotype, have 2 eyes. Cross a heterozygous female (2 eyes) with a 3 eyed male. What % of the children would have 2 eyes? What % of the boys would have 2 eyes? What % of the girls would have 3 eyes?

% 2 eyed children ______

% 2 eyed boys______

% 3 eyed girls______

6. If ½ of the boys from a cross have hemophilia (an X-linked recessive disease) and ½ the girls are carriers, what would be the genotypes of the parents? What would be the parental phenotypes?

Genotypes - Father______Mother ______

Phenotypes – Father______Mother ______

Questions 7 and 8 are slightly more fun and difficult. Read carefully

7. Vorbirows, a new species of seahorse found in the Pacific Ocean is being studied by scientists at USC. Because the scientists there are unintelligent, they have asked you to help them study the Vorbirow’s genetics. All Vorbirows they found are red, but when scientists crossed 2 red Vorbirows, one of the babies was yellow. Please help explain to them how this could have happened, including the type of inheritance. (X-linked recessive, Autosomal Dominant, etc.) Remember the USC scientists are mentally challenged, so be clear in your explanation and be sure to use a punnett square.

8. Anteaters are known for their long nose that they use to eat ants (hence the name). The length of their nose-short, medium, or long-is a result of their genes. Male anteaters have only ever been found with short or long length noses. Female anteaters of all lengths, short, medium and long have been found, although short noses are somewhat rare in females. Please Explain. Think about how the genes are passed to their children (autosomal dominant, autosomal recessive, X-linked dominant or X-linked recessive).