Homework #7

Select all true statements about dominate alleles. - Dominant alleles can mask the presence of a recessive allele - Dominant alleles are stronger than recessive alleles - Dominant alleles code for functioning proteins - Dominant alleles are always the most common allele in a population - Dominant alleles can be hidden

- Dominant alleles can mask the presence of a recessive allele - Dominant alleles code for functioning proteins

Alleles of a single gene control whether individuals have a "hitchhiker's thumb" or "straight thumb." You are studying the inheritance of hitchhiker's thumb (straight thumb is dominant) in your family. Assuming that this trait is inherited on an autosome (ie, not a sex-chromosome), please answer which of the following outcomes ARE POSSIBLE under normal circumstances. (Choose all that apply.) - Mother has straight thumb, father has hitchhiker's thumb. They have one child with straight thumb, another child with hitchhiker's thumb. - Mother has straight thumb, father has hitchhiker's thumb, child is homozygous dominant for the allele. - Two parents have straight thumb, but they have a child with hitchhiker's thumb. - Two parents have hitchhiker's thumb, but they have a child with straight thumb.

- Mother has straight thumb, father has hitchhiker's thumb. They have one child with straight thumb, another child with hitchhiker's thumb. - Two parents have straight thumb, but they have a child with hitchhiker's thumb.

Select all true statements about recessive alleles. - Recessive alleles can be hidden by dominant alleles - Dominant alleles can mask the presence of a recessive allele - Recessive alleles usually code for proteins that do not function - It is possible for a recessive allele to be the most common allele in a population - Recessive alleles are weaker than dominant alleles - Recessive alleles code for functioning proteins

- Recessive alleles can be hidden by dominant alleles - Dominant alleles can mask the presence of a recessive allele - Recessive alleles usually code for proteins that do not function - It is possible for a recessive allele to be the most common allele in a population

Alleles of a single gene control whether individuals have a "hitchhiker's thumb" or "straight thumb." You are studying the inheritance of hitchhiker's thumb (straight thumb is dominant) in your family. Assuming that this trait is inherited on an autosome (ie, not a sex-chromosome), please answer which of the following outcomes ARE POSSIBLE under normal circumstances. (Choose all that apply.) - Two parents have straight thumb, but they have a child with hitchhiker's thumb. - Mother has straight thumb, father has hitchhiker's thumb, child is homozygous dominant for the allele. - Mother has straight thumb, father has hitchhiker's thumb. They have one child with straight thumb, another child with hitchhiker's thumb. - Two parents have hitchhiker's thumb, but they have a child with straight thumb.

- Two parents have straight thumb, but they have a child with hitchhiker's thumb. - Mother has straight thumb, father has hitchhiker's thumb. They have one child with straight thumb, another child with hitchhiker's thumb.

You are studying green colorblindness in your family (colorblindness is recessive and on the X-chromosome). Please answer which of the following observations is NOT possible under normal circumstances: (Please check all that apply) - Your mom and dad are not colorblind, but your sister is colorblind. - Your mom and sister are colorblind, but your dad is not colorblind. - Your mom and sister are not colorblind, but your dad is colorblind. - Your dad and sister are colorblind, but your mom is not colorblind. - Your mom and dad are not colorblind, but your brother is colorblind.

- Your mom and dad are not colorblind, but your sister is colorblind. - Your mom and sister are colorblind, but your dad is not colorblind.

Suppose a woman is a symptomless carrier of a recessive x-linked disease. If her husband has the disease, what is the chance that their first child is a girl who also has the disease?

25%

Straight hair is dominant to curly. However, heterozygotes of this gene have wavy hair. If a mother with wavy hair mates with a father with straight hair, what would be the genotype ratio of the possible offspring?

2:2:0

what is the heredity pattern for Polygenetics with possible outcome?

A highly variable and wide range of several phenotypes can be observed.

In rose bushes, red flowers are dominant to white flowers. A purebred (homozygous) red rose is crossed with a white rose. Two roses from this parental cross (two of the F1 offspring) are then crossed. What will be the most common genotype of the next generation (F2) ?

Heterozygous

Suppose that there are two possible alleles for shell color in conchs; brown or white. Match the heredity pattern with the possible expression of these alleles for Mendel hereditary.

Homozygous dominant and heterozygous individuals are brown, while homozygous recessive individuals are white.

Suppose that there are two possible alleles for shell color in conchs; brown or white. Match the heredity pattern with the possible expression of these alleles for Incomplete dominance.

Homozygous dominant individuals are brown, homozygous individuals are white, and heterozygotes are a very light, faded brown.

Suppose that there are two possible alleles for shell color in conchs; brown or white. Match the heredity pattern with the possible expression of these alleles for Codominance.

Homozygous dominant individuals are brown, homozygous recessive individuals are white, and heterozygotes have patches of brown and white.

Albinism is characterized by the lack of a dark pigment called melanin in the hair, skin and eyes. Albinism is caused by the absence of an functioning enzyme called thyrosinase, which is necessary for the synthesis of melanin. Given this bit of information, what can you assume about the heredity pattern of this trait?

It is caused by a recessive allele of the gene coding for thyrosinase

what is the heredity pattern for Multiple alleles with possible outcome?

More than three phenotypes can be observed for a single gene.

what is the heredity pattern for Y-linked with possible outcome?

Only males can express these traits.

what is the heredity pattern for Mendel Genetics with possible outcome?

Only two variations of a trait are observed. Dominant alleles are fully expressed while recessive alleles will be hidden in heterozygotes.

In Mexican hairless dogs, a dominant allele codes for hairlessness. However, inheriting two dominant alleles is lethal; the fetus dies before birth. Suppose a breeder mates two dogs that are heterozygous for the hair allele. What are the predicted genotype and phenotype ratios of the puppies that are born?

Phenotype Ratio 2:1 Genotype Ratio: 0:2:1

In an attempt to breed winter barley that is resistant to barley mosaic virus, agricultural researchers cross a susceptible domesticated strain with a resistant wild strain. The F1 plants are all susceptible, but when the F1 plants are crossed with each other, some of the F2 individuals are resistant. Is the resistance allele recessive or dominant? (Note: susceptible means able to get the viral disease, while resistant means not able to get the disease)

The resistance allele must be recessive

what is the heredity pattern for Incomplete Dominance with possible outcome?

Three variations of a trait can be observed. Heterozygotes are an intermediate blend of the dominant and recessive traits.

what is the heredity pattern for Codominance with possible outcome?

Three variations of a trait can be observed. The dominant and recessive trait variations are both fully expressed in heterozygotes.

what is a gene?

a portion of DNA whose sequence of nucleotides code for a protein.

what is an allele?

a variation of a gene.

the heredity pattern of Codominance with its best description.

both alleles are fully dominant.

Homologous chromosomes contain the same _________________, but may not contain the same ________________.

genes; alleles

Straight hair is dominant to curly. However, heterozygotes of this gene have wavy hair. What inheritance pattern do these traits follow?

incomplete dominance

A gene's _____________ is its physical place on a chromosome.

locus

the heredity pattern of Incomplete dominance with its best description.

neither allele is fully dominant or recessive.

the heredity pattern of Mendel Heredity with its best description.

only two alleles for a trait, either dominant or recessive.

what is a genotype?

the combination of alleles an organism has.

According to Mendel, if an individual is heterozygous for a gene, the phenotype will correspond to that of

the dominant trait alone

the heredity pattern of Sex-Linkage with its best description.

the gene is located in either the x or y chromosome.

what is a phenotype?

the observable traits of an organism

the heredity pattern of Polygenetics with its best description.

traits are governed by more than one gene.

the heredity pattern of Multiple alleles with its best description.

traits are governed by more than two variations of a gene.