Inheritance - GRE
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A scientist has been working with a new species of plant. He has found that there are two separate genes, which segregate according to standard Mendelian genetics, that are capable of producing the same phenotype. A single dominant allele from either gene confers red coloration of the plant's flowers. Without any dominant alleles the flowers are white. If he crosses two plants heterozygous for both traits, what will be the resulting phenotypic ratios of the offspring?
A scientist has been working with a new species of plant. He has found that there are two separate genes, which segregate according to standard Mendelian genetics, that are capable of producing the same phenotype. A single dominant allele from either gene confers red coloration of the plant's flowers. Without any dominant alleles the flowers are white. If he crosses two plants heterozygous for both traits, what will be the resulting phenotypic ratios of the offspring?
This problem requires a standard dihybrid cross. The crossed genotypes are AaBb x AaBb. This results in a phenotypic ratio of 9 dominant for both traits, 3 dominant for a single trait, 3 dominant for the other trait, and 1 recessive for both traits. In this cross, it will result in: 9 AxBx, 3 Axbb, 3 aaBx, and 1 aabb.
Since we know that the genes are both capable of making the red coloration we actually need to add together all of the choices that contain at least a single dominant allele. Essentially, AxBx, Axbb, and aaBx all show the exact same phenotype. This leaves us with a 15:1 ratio of red to white flowers.
This problem requires a standard dihybrid cross. The crossed genotypes are AaBb x AaBb. This results in a phenotypic ratio of 9 dominant for both traits, 3 dominant for a single trait, 3 dominant for the other trait, and 1 recessive for both traits. In this cross, it will result in: 9 AxBx, 3 Axbb, 3 aaBx, and 1 aabb.
Since we know that the genes are both capable of making the red coloration we actually need to add together all of the choices that contain at least a single dominant allele. Essentially, AxBx, Axbb, and aaBx all show the exact same phenotype. This leaves us with a 15:1 ratio of red to white flowers.
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In a species of ant, black coloration is dominant to white. A scientist is operating under the assumption that this gene follows basic Mendelian principles; however, after crossing two heterozygotes he obtained a ratio of 2:1 of dominant to recessive offspring. Which of the following could explain this result?
In a species of ant, black coloration is dominant to white. A scientist is operating under the assumption that this gene follows basic Mendelian principles; however, after crossing two heterozygotes he obtained a ratio of 2:1 of dominant to recessive offspring. Which of the following could explain this result?
The only answer that properly explains a 2:1 ratio is if the homozygous dominant phenotype is lethal. In our punnett square, this would give a two-thirds chance for a heterozygous offspring and a one-third chance for a recessive offspring. We know the recessive phenotype is not lethal because homozygous recessive offspring were produced.
Parents: Aa x Aa
Offspring genotypes: AA, Aa, Aa, aa
Offspring phenotypes: lethal, dominant, dominant, recessive (only three live offspring produced)
Offspring ratio: 2 dominant to 1 recessive
There is also no evidence that codominance or incomplete dominance is present. If black and white spotted offspring or gray offspring were produced then these theories would have merit.
The only answer that properly explains a 2:1 ratio is if the homozygous dominant phenotype is lethal. In our punnett square, this would give a two-thirds chance for a heterozygous offspring and a one-third chance for a recessive offspring. We know the recessive phenotype is not lethal because homozygous recessive offspring were produced.
Parents: Aa x Aa
Offspring genotypes: AA, Aa, Aa, aa
Offspring phenotypes: lethal, dominant, dominant, recessive (only three live offspring produced)
Offspring ratio: 2 dominant to 1 recessive
There is also no evidence that codominance or incomplete dominance is present. If black and white spotted offspring or gray offspring were produced then these theories would have merit.
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A child is curious to know what his blood type is, but he only knows his parents' blood types. If his mother had blood type A and his father had blood type AB, what are the potential blood types the child might have?
A child is curious to know what his blood type is, but he only knows his parents' blood types. If his mother had blood type A and his father had blood type AB, what are the potential blood types the child might have?
We are not given the mother's full genotype in the question; she could reasonably carry two A alleles, or an A allele and a recessive O allele. We know that the father must carry one copy of the A allele and one copy of the B allele.
Two punnett squares can answer this question, corresponding to the two possible maternal genotypes: one crossing AA x AB and the other crossing AO x AB. From the first cross there is a 50% chance of blood type A versus 50% chance of blood type AB (half AA and half AB). The second cross shows that there is a potential chance of 50% for type A, 25% for type AB, and 25% for type B (one AA, one OA, one AB, and one OB).
Based on these possibilities, the child could have blood type A, B, or AB. The child cannot have blood type O.
We are not given the mother's full genotype in the question; she could reasonably carry two A alleles, or an A allele and a recessive O allele. We know that the father must carry one copy of the A allele and one copy of the B allele.
Two punnett squares can answer this question, corresponding to the two possible maternal genotypes: one crossing AA x AB and the other crossing AO x AB. From the first cross there is a 50% chance of blood type A versus 50% chance of blood type AB (half AA and half AB). The second cross shows that there is a potential chance of 50% for type A, 25% for type AB, and 25% for type B (one AA, one OA, one AB, and one OB).
Based on these possibilities, the child could have blood type A, B, or AB. The child cannot have blood type O.
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A breeder performs a standard dihybrid cross between two plants that are heterozygous for both traits in question. How many unique genotypes could be present in the resulting offspring?
A breeder performs a standard dihybrid cross between two plants that are heterozygous for both traits in question. How many unique genotypes could be present in the resulting offspring?
There are nine distinct genotypes present after a standard dihybrid cross. This question can easily be answered by setting up a Punnett square (AaBb x AaBb) and counting the number of unique genotypes present after doing the cross. The numbers also conveniently work out that however many offspring display the dominant phenotype is equal to the number to of genotypes present (this is true for monohybrid and trihybrid crosses as well).
There are nine distinct genotypes present after a standard dihybrid cross. This question can easily be answered by setting up a Punnett square (AaBb x AaBb) and counting the number of unique genotypes present after doing the cross. The numbers also conveniently work out that however many offspring display the dominant phenotype is equal to the number to of genotypes present (this is true for monohybrid and trihybrid crosses as well).
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A scientist is performing a monohybrid homozygous cross: tall plants crossed with short plants. What fraction of the F2 generation are homozygous tall?
A scientist is performing a monohybrid homozygous cross: tall plants crossed with short plants. What fraction of the F2 generation are homozygous tall?
A monohybrid cross between two homozygous plants would involve a parental generation that looked like this: SS (tall) x ss (short). The F1 generation would produce only heterozygous tall plants (Ss). The F2 generation would produce offspring from the following cross: Ss x Ss. A punnett square would reveal that the F2 generation would have 25% homozygous tall (SS), 50% heterozygous tall (Ss), and 25% homozygous short plants. Note that we do not need information regarding which trait is dominant in this case, and we would still get the correct answer if we took short as the dominant phenotype.
A monohybrid cross between two homozygous plants would involve a parental generation that looked like this: SS (tall) x ss (short). The F1 generation would produce only heterozygous tall plants (Ss). The F2 generation would produce offspring from the following cross: Ss x Ss. A punnett square would reveal that the F2 generation would have 25% homozygous tall (SS), 50% heterozygous tall (Ss), and 25% homozygous short plants. Note that we do not need information regarding which trait is dominant in this case, and we would still get the correct answer if we took short as the dominant phenotype.
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In apple trees, the allele for white blossoms is dominant over the allele for pink blossoms. Two trees heterozygous for this gene are crossed. What is the phenotype ratio of the offspring?
In apple trees, the allele for white blossoms is dominant over the allele for pink blossoms. Two trees heterozygous for this gene are crossed. What is the phenotype ratio of the offspring?
The crossing of two heterozygous parents will yield 1 homozyougs dominant offspring, 1 homozygous recessive offspring and 2 heterozygous offspring. Since white blossoms is the dominant allele, the heterozygous offspring will be white leading to a phenotypic ratio of 3 white : 1 pink blossom.
The crossing of two heterozygous parents will yield 1 homozyougs dominant offspring, 1 homozygous recessive offspring and 2 heterozygous offspring. Since white blossoms is the dominant allele, the heterozygous offspring will be white leading to a phenotypic ratio of 3 white : 1 pink blossom.
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Assume complete dominance inheritance for the following question.
A pure-breeding red flower is mated with a pure-breeding white flower. All offspring are red in color; this is the F1 generation. Two of these offspring flowers are then mated with one another, and have F2 offspring.
Which of the following is true of the F2 offspring?
Assume complete dominance inheritance for the following question.
A pure-breeding red flower is mated with a pure-breeding white flower. All offspring are red in color; this is the F1 generation. Two of these offspring flowers are then mated with one another, and have F2 offspring.
Which of the following is true of the F2 offspring?
Since we had pure-breeding parents (also known as homozygotes for their respective colors), we can safely say the F1 offspring are heterozygotes and have a red allele and a white allele. When crossing these offspring with one another, we will expect to get a 3:1 ratio of red to white flowers. Not all flowers will be red, but 75% of the flowers will be.
Shown below is the punnett square that reflects this conclusion. (Note that "A" represents a red allele and "a" represents a white allele):
A a
A AA (red) Aa (red)
a Aa (red) aa (white)
Since we had pure-breeding parents (also known as homozygotes for their respective colors), we can safely say the F1 offspring are heterozygotes and have a red allele and a white allele. When crossing these offspring with one another, we will expect to get a 3:1 ratio of red to white flowers. Not all flowers will be red, but 75% of the flowers will be.
Shown below is the punnett square that reflects this conclusion. (Note that "A" represents a red allele and "a" represents a white allele):
A a
A AA (red) Aa (red)
a Aa (red) aa (white)
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Each of the listed statements about transposable genetic elements in eukaryotic genomes are true except for which one?
Each of the listed statements about transposable genetic elements in eukaryotic genomes are true except for which one?
Transposable elements are divided into two categories: Type 1 (retrotransposons), which form RNA intermediates, and type 2 (transposons), which do not form RNA intermediates and directly enter a new site. Transposase proteins regulate the translocation of type 2 transposable elements, which do not require a RNA intermediate.
Transposable elements are divided into two categories: Type 1 (retrotransposons), which form RNA intermediates, and type 2 (transposons), which do not form RNA intermediates and directly enter a new site. Transposase proteins regulate the translocation of type 2 transposable elements, which do not require a RNA intermediate.
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Crossing foxes that are double heterozygotes for two genes regulating coat color yields 27 grey, 12 red and 9 black offspring. What mechanism explains the ratio of coat color observed in the offspring?
Crossing foxes that are double heterozygotes for two genes regulating coat color yields 27 grey, 12 red and 9 black offspring. What mechanism explains the ratio of coat color observed in the offspring?
If this were a Mendelian trait, we would expect a 9:3:3:1 ratio of offspring coat color. However, the results show a 9:4:3 ratio. Epistatic interaction between genes can be identified by one gene masking the phenotype of another gene. In this case, the double homozygote phenotype was masked by the red coat color phenotype (4 offspring, instead of seeing 3 red offspring). This suggests that the two coat color genes are epistatic.
If this were a Mendelian trait, we would expect a 9:3:3:1 ratio of offspring coat color. However, the results show a 9:4:3 ratio. Epistatic interaction between genes can be identified by one gene masking the phenotype of another gene. In this case, the double homozygote phenotype was masked by the red coat color phenotype (4 offspring, instead of seeing 3 red offspring). This suggests that the two coat color genes are epistatic.
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When the expression and subsequent phenotype of one gene is dependent on the expression of another gene, this type of phenonemon is known as                     .
When the expression and subsequent phenotype of one gene is dependent on the expression of another gene, this type of phenonemon is known as                     .
The correct answer is epistasis. Complete dominance, codominance, and incomplete dominance describe the expression of only one gene (one set of alleles) that do not depend on the expression of other genes. Gene masking is not a phenomenon in genetics.
The correct answer is epistasis. Complete dominance, codominance, and incomplete dominance describe the expression of only one gene (one set of alleles) that do not depend on the expression of other genes. Gene masking is not a phenomenon in genetics.
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Which of the following are examples of codominance?
I. A person with blood type AB
II. A flower that displays a red and white spotted phenotype (both colors are attributed to the same gene; homozygosity for either color makes a flower that is completely red or white)
III. A flower that displays a pink phenotype (a homozygous dominant flower is red and a homozygous recessive flower is white)
IV. An organism whose heterozygous phenotype is identical to the homozygous dominant phenotype
Which of the following are examples of codominance?
I. A person with blood type AB
II. A flower that displays a red and white spotted phenotype (both colors are attributed to the same gene; homozygosity for either color makes a flower that is completely red or white)
III. A flower that displays a pink phenotype (a homozygous dominant flower is red and a homozygous recessive flower is white)
IV. An organism whose heterozygous phenotype is identical to the homozygous dominant phenotype
Codominance occurs when both phenotypes are displayed equally and independently in the phenotype (without blending). This is the case with blood type and the red and white spotted flower. A person with blood type AB expresses proteins that will recognize both type A and type B. The red and white spotted flower equally expresses the two color phenotypes.
The pink flower is an example of incomplete dominance (blended phenotype). Option IV describes a normal dominant-recessive hierarchy, where only one copy of the dominant allele is needed to display the dominant phenotype.
Codominance occurs when both phenotypes are displayed equally and independently in the phenotype (without blending). This is the case with blood type and the red and white spotted flower. A person with blood type AB expresses proteins that will recognize both type A and type B. The red and white spotted flower equally expresses the two color phenotypes.
The pink flower is an example of incomplete dominance (blended phenotype). Option IV describes a normal dominant-recessive hierarchy, where only one copy of the dominant allele is needed to display the dominant phenotype.
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A student determines that color for a new diploid species is conferred by one gene. The student mates a homozygous dominant red mother with a homozygous recessive green father to yeild 100% of offspring that are both red and green. What form of inheritance best describes this?
A student determines that color for a new diploid species is conferred by one gene. The student mates a homozygous dominant red mother with a homozygous recessive green father to yeild 100% of offspring that are both red and green. What form of inheritance best describes this?
The correct answer is codominance. According to this mode of inheritance, individuals that are heterozygous for a condition express both alleles equally. If the offspring were exhibited incomplete dominance, their phenotype would have been a red-green blend because the heterozygous condition is a blend of both alleles. Complete dominance occurs when the heterozygous condition exhibits the same phenotype as the homozygous dominant. In epistasis, the expression of one gene is dependent on the expression of a second, which is a form of inheritance that does not apply to this question. Finally, a polygenic trait is a trait that is conferred by multiple genes, a situation for which we know is not the case in this question.
The correct answer is codominance. According to this mode of inheritance, individuals that are heterozygous for a condition express both alleles equally. If the offspring were exhibited incomplete dominance, their phenotype would have been a red-green blend because the heterozygous condition is a blend of both alleles. Complete dominance occurs when the heterozygous condition exhibits the same phenotype as the homozygous dominant. In epistasis, the expression of one gene is dependent on the expression of a second, which is a form of inheritance that does not apply to this question. Finally, a polygenic trait is a trait that is conferred by multiple genes, a situation for which we know is not the case in this question.
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Human beings are capable of having A, B, AB or O blood. While "A" and "B" alleles can be expressed at the same time on red blood cells, O type blood can only be a phenotype if a person has 2 "O" alleles.
Based on this information, what two modes of inheritance contribute to blood type in human beings?
Human beings are capable of having A, B, AB or O blood. While "A" and "B" alleles can be expressed at the same time on red blood cells, O type blood can only be a phenotype if a person has 2 "O" alleles.
Based on this information, what two modes of inheritance contribute to blood type in human beings?
Since A and B can be expressed at the same time on a red blood cell, we can say that A and B are codominant to one another. On the other hand, this cannot be said for the O allele. If a person has an A allele and an O allele, that person will have type A blood. Both A and B are dominant over O. As a result, we also see complete dominance take place with blood types. To help solidify this concept, added below is a genotype/phentoype comparison:
A/A = A blood
A/O = A blood
O/O = O blood
B/B = B blood
B/O = B blood
A/B = AB blood
Since A and B can be expressed at the same time on a red blood cell, we can say that A and B are codominant to one another. On the other hand, this cannot be said for the O allele. If a person has an A allele and an O allele, that person will have type A blood. Both A and B are dominant over O. As a result, we also see complete dominance take place with blood types. To help solidify this concept, added below is a genotype/phentoype comparison:
A/A = A blood
A/O = A blood
O/O = O blood
B/B = B blood
B/O = B blood
A/B = AB blood
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In a species of ant, black coloration is dominant to white. A scientist is operating under the assumption that this gene follows basic Mendelian principles; however, after crossing two heterozygotes he obtained a ratio of 2:1 of dominant to recessive offspring. Which of the following could explain this result?
In a species of ant, black coloration is dominant to white. A scientist is operating under the assumption that this gene follows basic Mendelian principles; however, after crossing two heterozygotes he obtained a ratio of 2:1 of dominant to recessive offspring. Which of the following could explain this result?
The only answer that properly explains a 2:1 ratio is if the homozygous dominant phenotype is lethal. In our punnett square, this would give a two-thirds chance for a heterozygous offspring and a one-third chance for a recessive offspring. We know the recessive phenotype is not lethal because homozygous recessive offspring were produced.
Parents: Aa x Aa
Offspring genotypes: AA, Aa, Aa, aa
Offspring phenotypes: lethal, dominant, dominant, recessive (only three live offspring produced)
Offspring ratio: 2 dominant to 1 recessive
There is also no evidence that codominance or incomplete dominance is present. If black and white spotted offspring or gray offspring were produced then these theories would have merit.
The only answer that properly explains a 2:1 ratio is if the homozygous dominant phenotype is lethal. In our punnett square, this would give a two-thirds chance for a heterozygous offspring and a one-third chance for a recessive offspring. We know the recessive phenotype is not lethal because homozygous recessive offspring were produced.
Parents: Aa x Aa
Offspring genotypes: AA, Aa, Aa, aa
Offspring phenotypes: lethal, dominant, dominant, recessive (only three live offspring produced)
Offspring ratio: 2 dominant to 1 recessive
There is also no evidence that codominance or incomplete dominance is present. If black and white spotted offspring or gray offspring were produced then these theories would have merit.
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A scientist has been working with a new species of plant. He has found that there are two separate genes, which segregate according to standard Mendelian genetics, that are capable of producing the same phenotype. A single dominant allele from either gene confers red coloration of the plant's flowers. Without any dominant alleles the flowers are white. If he crosses two plants heterozygous for both traits, what will be the resulting phenotypic ratios of the offspring?
A scientist has been working with a new species of plant. He has found that there are two separate genes, which segregate according to standard Mendelian genetics, that are capable of producing the same phenotype. A single dominant allele from either gene confers red coloration of the plant's flowers. Without any dominant alleles the flowers are white. If he crosses two plants heterozygous for both traits, what will be the resulting phenotypic ratios of the offspring?
This problem requires a standard dihybrid cross. The crossed genotypes are AaBb x AaBb. This results in a phenotypic ratio of 9 dominant for both traits, 3 dominant for a single trait, 3 dominant for the other trait, and 1 recessive for both traits. In this cross, it will result in: 9 AxBx, 3 Axbb, 3 aaBx, and 1 aabb.
Since we know that the genes are both capable of making the red coloration we actually need to add together all of the choices that contain at least a single dominant allele. Essentially, AxBx, Axbb, and aaBx all show the exact same phenotype. This leaves us with a 15:1 ratio of red to white flowers.
This problem requires a standard dihybrid cross. The crossed genotypes are AaBb x AaBb. This results in a phenotypic ratio of 9 dominant for both traits, 3 dominant for a single trait, 3 dominant for the other trait, and 1 recessive for both traits. In this cross, it will result in: 9 AxBx, 3 Axbb, 3 aaBx, and 1 aabb.
Since we know that the genes are both capable of making the red coloration we actually need to add together all of the choices that contain at least a single dominant allele. Essentially, AxBx, Axbb, and aaBx all show the exact same phenotype. This leaves us with a 15:1 ratio of red to white flowers.
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A child is curious to know what his blood type is, but he only knows his parents' blood types. If his mother had blood type A and his father had blood type AB, what are the potential blood types the child might have?
A child is curious to know what his blood type is, but he only knows his parents' blood types. If his mother had blood type A and his father had blood type AB, what are the potential blood types the child might have?
We are not given the mother's full genotype in the question; she could reasonably carry two A alleles, or an A allele and a recessive O allele. We know that the father must carry one copy of the A allele and one copy of the B allele.
Two punnett squares can answer this question, corresponding to the two possible maternal genotypes: one crossing AA x AB and the other crossing AO x AB. From the first cross there is a 50% chance of blood type A versus 50% chance of blood type AB (half AA and half AB). The second cross shows that there is a potential chance of 50% for type A, 25% for type AB, and 25% for type B (one AA, one OA, one AB, and one OB).
Based on these possibilities, the child could have blood type A, B, or AB. The child cannot have blood type O.
We are not given the mother's full genotype in the question; she could reasonably carry two A alleles, or an A allele and a recessive O allele. We know that the father must carry one copy of the A allele and one copy of the B allele.
Two punnett squares can answer this question, corresponding to the two possible maternal genotypes: one crossing AA x AB and the other crossing AO x AB. From the first cross there is a 50% chance of blood type A versus 50% chance of blood type AB (half AA and half AB). The second cross shows that there is a potential chance of 50% for type A, 25% for type AB, and 25% for type B (one AA, one OA, one AB, and one OB).
Based on these possibilities, the child could have blood type A, B, or AB. The child cannot have blood type O.
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A breeder performs a standard dihybrid cross between two plants that are heterozygous for both traits in question. How many unique genotypes could be present in the resulting offspring?
A breeder performs a standard dihybrid cross between two plants that are heterozygous for both traits in question. How many unique genotypes could be present in the resulting offspring?
There are nine distinct genotypes present after a standard dihybrid cross. This question can easily be answered by setting up a Punnett square (AaBb x AaBb) and counting the number of unique genotypes present after doing the cross. The numbers also conveniently work out that however many offspring display the dominant phenotype is equal to the number to of genotypes present (this is true for monohybrid and trihybrid crosses as well).
There are nine distinct genotypes present after a standard dihybrid cross. This question can easily be answered by setting up a Punnett square (AaBb x AaBb) and counting the number of unique genotypes present after doing the cross. The numbers also conveniently work out that however many offspring display the dominant phenotype is equal to the number to of genotypes present (this is true for monohybrid and trihybrid crosses as well).
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A scientist is performing a monohybrid homozygous cross: tall plants crossed with short plants. What fraction of the F2 generation are homozygous tall?
A scientist is performing a monohybrid homozygous cross: tall plants crossed with short plants. What fraction of the F2 generation are homozygous tall?
A monohybrid cross between two homozygous plants would involve a parental generation that looked like this: SS (tall) x ss (short). The F1 generation would produce only heterozygous tall plants (Ss). The F2 generation would produce offspring from the following cross: Ss x Ss. A punnett square would reveal that the F2 generation would have 25% homozygous tall (SS), 50% heterozygous tall (Ss), and 25% homozygous short plants. Note that we do not need information regarding which trait is dominant in this case, and we would still get the correct answer if we took short as the dominant phenotype.
A monohybrid cross between two homozygous plants would involve a parental generation that looked like this: SS (tall) x ss (short). The F1 generation would produce only heterozygous tall plants (Ss). The F2 generation would produce offspring from the following cross: Ss x Ss. A punnett square would reveal that the F2 generation would have 25% homozygous tall (SS), 50% heterozygous tall (Ss), and 25% homozygous short plants. Note that we do not need information regarding which trait is dominant in this case, and we would still get the correct answer if we took short as the dominant phenotype.
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In apple trees, the allele for white blossoms is dominant over the allele for pink blossoms. Two trees heterozygous for this gene are crossed. What is the phenotype ratio of the offspring?
In apple trees, the allele for white blossoms is dominant over the allele for pink blossoms. Two trees heterozygous for this gene are crossed. What is the phenotype ratio of the offspring?
The crossing of two heterozygous parents will yield 1 homozyougs dominant offspring, 1 homozygous recessive offspring and 2 heterozygous offspring. Since white blossoms is the dominant allele, the heterozygous offspring will be white leading to a phenotypic ratio of 3 white : 1 pink blossom.
The crossing of two heterozygous parents will yield 1 homozyougs dominant offspring, 1 homozygous recessive offspring and 2 heterozygous offspring. Since white blossoms is the dominant allele, the heterozygous offspring will be white leading to a phenotypic ratio of 3 white : 1 pink blossom.
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Assume complete dominance inheritance for the following question.
A pure-breeding red flower is mated with a pure-breeding white flower. All offspring are red in color; this is the F1 generation. Two of these offspring flowers are then mated with one another, and have F2 offspring.
Which of the following is true of the F2 offspring?
Assume complete dominance inheritance for the following question.
A pure-breeding red flower is mated with a pure-breeding white flower. All offspring are red in color; this is the F1 generation. Two of these offspring flowers are then mated with one another, and have F2 offspring.
Which of the following is true of the F2 offspring?
Since we had pure-breeding parents (also known as homozygotes for their respective colors), we can safely say the F1 offspring are heterozygotes and have a red allele and a white allele. When crossing these offspring with one another, we will expect to get a 3:1 ratio of red to white flowers. Not all flowers will be red, but 75% of the flowers will be.
Shown below is the punnett square that reflects this conclusion. (Note that "A" represents a red allele and "a" represents a white allele):
A a
A AA (red) Aa (red)
a Aa (red) aa (white)
Since we had pure-breeding parents (also known as homozygotes for their respective colors), we can safely say the F1 offspring are heterozygotes and have a red allele and a white allele. When crossing these offspring with one another, we will expect to get a 3:1 ratio of red to white flowers. Not all flowers will be red, but 75% of the flowers will be.
Shown below is the punnett square that reflects this conclusion. (Note that "A" represents a red allele and "a" represents a white allele):
A a
A AA (red) Aa (red)
a Aa (red) aa (white)
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