Exam 19: Introduction to Genetics

If all offspring of a cross have the genotype Aa , the parents of the crosses would most likely be

Gene A occurs on chromosome 5, gene B is on chromosome 21. Therefore, these two parts of the chromosomes CANNOT be

Persons who inherit a gene for extra fingers or toes ____ have the physical manifestation.

In a certain breed of chicken, two genes control color. A dominant allele ( I ) inhibits expression of any color gene ( C ). A second recessive gene ( c ) results in albinism when homozygous ( cc ). Give the F ₂ white phenotypic ratio of a colored chicken ii CC with a chicken II cc .

In mice, the allele for colored fur ( C ) is dominant to the allele for albinism ( c ). The allele ( W ) for normal behavior is dominant to that for waltzing movement ( w ). Give the probable genotypes of the parents if they produced the offspring listed after the following crosses: (a) Colored normal x white waltzer produced 10 colored normal, 8 colored waltzers, 2 white waltzers, and 11 white normal. (b) Colored normal x white normal produced 35 colored normal and 13 colored waltzers. (c) Colored normal x colored normal produced 37 colored normal, 14 colored waltzers, 9 white normal, and 5 white waltzers.

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring that is pure-breeding?

A particular blood type is determined by

If two copies of a gene are identical alleles, the condition is referred to as

When an individual with an unknown genotype is crossed with an individual that is homozygous recessive for the trait being studied, the procedure is called a

If two copies of a gene are different alleles, the condition is referred to as

The usual F ₂ phenotypic ratio of a dihybrid cross is

ABO blood types are controlled by

The chance of producing an offspring of genotype Aa Bb cc from a cross of Aa BB Cc with Aa BB Cc is

Heterozygotes with the genotype Hb^A/Hb^S have

The squares at #2 represent the ____ of the ____.

If all the offspring of a cross had the genotype Aa Bb , the parents of the cross would most likely be

In a certain breed of chicken, an incompletely dominant gene controls color. The homozygous black, when crossed with the homozygous splashed-white, produces an intermediate gray color pattern called blue. A second gene controls the shape of the comb. The dominant allele ( R ) produces rose, while the recessive allele ( r ) produces single. Give the F ₁ and F ₂ genotypic and phenotypic ratios of a cross between a pure-breeding, black single and a pure-breeding, splashed-white rose.

White fruit color in summer squash is influenced by a dominant allele W , while colored fruit must be ww . In the presence of ww , a dominant gene G results in yellow fruit, and if the individual had both recessive genes in the homozygous condition, it would be green. Give the F ₂ phenotypic ratios resulting from a cross of a pure-breeding white of genotype WW GG with a green.

When an allele's effect on a trait is masked by that of an allele paired with it, the second allele is referred to as

In a monohybrid cross, what kind of genes "disappear" in the F ₁ generation?