Chapter 11
What would be the expected frequency of agouti brown offspring in the litter?
3/16
Which of the following statements best explains the outcome of this cross?
The forked mutation and the twist mutation are codominant alleles of the same locus
Height in humans generally shows a normal (bell-shaped) distribution. What type of inheritance most likely determines height?
a combination of polygenic inheritance and environmental factors
In order to discern patterns in the distribution of alleles, it is helpful to sketch a curve over the bars of the histogram, and a line through the highest bar. (Figure 2) What pattern does the distribution of frequency values show in this histogram?
a normal distribution, characterized by frequencies that are symmetrically distributed around one central peak value
What is the genotype of the parent with orange eyes and white skin? (Note: orange eyes are recessive.)
bbgg
A phenotypic ratio of 9:3:3:1 in the offspring of a cross indicates that _____.
both parents are heterozygous for both genes
Can you match these prefixes, suffixes, and word roots with their definitions?
change, after: meta- enzyme: -ase within: intra- three: tri- milk: lact- one-half: semi- across: trans- blood: hem- (or hemato-) different, other: hetero-
Predict genotypic and phenotypic ratios for this cross.
genotypic ratio of 1 Ii : 1 ii and a phenotypic ratio of 1 inflated : 1 constricted
In the essay, the point is made that the right questions must be asked when designing an experiment that measures how genetics and environment "shape who we are." Which of the following measurements is probably the least valuable in such an experiment?
the average lifespan
During which part of meiosis (meiosis I or meiosis II) do the two alleles of a gene separate? During which phase does the separation occur?
meiosis I, anaphase
CH 11 HW 1
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CHAPTER 11 MC
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Two organisms with genotype AaBbCcDdEE mate. These loci are all independent. What fraction of the offspring will have the same genotype as the parents?
1/16
What is the probability that this pair would produce the indicated offspring? (Assume independent assortment of all gene pairs.) aaBbCC ×× AABbcc →→ AaBbCc
1/2
When an F1 plant undergoes meiosis, what gamete types will it produce, and in what proportions?
1/2 Y 1/2 y
Jane and John are considering having another child. Given the pedigree you constructed and the mode of inheritance for galactosemia, what is the risk that their next child will have the disorder?
1/4
If a plant that is heterozygous for all three characters is allowed to self-fertilize, what proportion of the offspring would you expect to be homozygous for the three dominant traits? Express your answer as a fraction using the slash symbol and no spaces (for example, 1/16).
1/64
What proportion of the offspring would you expect to be homozygous for the three recessive traits?
1/64
What proportion of the offspring would you expect to be heterozygous for all three characters?
1/8
In a situation in which genes assort independently, what is the ratio of the gametes produced by an AaBB individual?
1AB : 1 aB
If Sophie has a brother or sister from the same parents, what are the chances that sibling would have cystic fibrosis?
25%
When crossing an organism that is homozygous recessive for a single trait with one that is heterozygous for the same trait, what is the chance of producing an offspring with the homozygous recessive phenotype?
50%
Fraternal twins share _____ of the same genes, while identical twins share _____ of the same genes.
50% on average; 100%
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
8
What is the difference between heterozygous and homozygous individuals?
All of the gametes from a homozygote carry the same version of the gene while those of a heterozygote will differ.
Which of the following do you expect if an individual is heterozygous for the sickle-cell trait?
Any child born of parents who are both able to taste PTC will inherit the ability to taste PTC.
How could the botanist best determine whether the genotype of the green-pod plant is homozygous or heterozygous?
Cross the green-pod plant with a yellow-pod plant.
Which of the following do you think contributed the most to the success of Rhys' gene therapy?
Doctors were replacing only one gene, and they only had to insert that gene into bone marrow cells.
True or false? In diploid organisms, a dominant phenotype will only be expressed if the individual is homozygous dominant for that trait.
False
Which of the following statements apply to the variation in human skin color?
Human skin color variation likely evolved in response to differences in the intensity of sunlight around the world. Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa. Human skin color variation is primarily determined by the type and amount of melanin pigment in the skin.
Select the correct explanation for the fact that a carrier of a recessive genetic disorder does not have the disorder.
In a recessive disorder, only a single functioning allele is necessary to determine a normal phenotype.
Which of the following is true about a plant with the genotype AABbcc?
It is homozygous at two loci.
What is the best explanation for the curve's shape?
It is now skewed toward a higher number of dark-skin alleles.
Folk singer Woody Guthrie died of Huntington's disease, an autosomal dominant disorder. Which statement below must be true?
It is very likely that at least one of Woody Guthrie's parents also had the allele for Huntington's disease.
That each gamete contains a single allele of the eye color gene is an illustration of _____.
Mendel's law of segregation only
In his breeding experiments, Mendel first crossed true-breeding plants to produce a second generation, which were then allowed to self-pollinate to generate the offspring. How do we name these three generations?
P ... F1 ... F2
The result of the following cross indicates that the genotype of the female parent is _____.
RR
You cross a true-breeding red-flowered snapdragon with a true-breeding white-flowered one. All of the F1 are pink. What does this say about the parental traits?
Red shows incomplete dominance over white.
Look at the Punnett square, which shows the predicted offspring of the F2 generation from a cross between a plant with yellow-round seeds (YYRR) and a plant with green-wrinkled seeds (yyrr). Select the correct statement about wrinkled yellow seeds in the F2 generation.
The chance that an individual taken at random from the F2 generation produces wrinkled seeds is 25% and the chance that the same individual produces yellow seeds is 75%.
Which of the following statements correctly describes one difference between the law of independent assortment and the law of segregation?
The law of independent assortment explains the segregation of two or more genes relative to one another.
What was an important limitation in the experiments shown in the video?
There were too few subjects. In other words, the sample size was too small.
Each chromosome in this homologous pair possesses a different allele for flower color. Which statement about this homologous pair of chromosomes is correct?
These homologous chromosomes represent a maternal and a paternal chromosome.
Quantitative characters vary in a population along a continuum. How do such characters differ from the characters investigated by Mendel in his experiments on peas?
They do not interact at all.
What was Mendel's explanation for his observation that traits that had disappeared in the F1 generation reappeared in the F2 generation of the pea plants he used in his experiments?
Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1.
HW Chapter 11 #2
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What is an allele?
an alternative version of a gene
Which of the following phases of cell division confirms Mendel's observation of the segregation of alleles in gamete formation?
anaphase I of meiosis
The result of the following cross indicates that genotypically the offspring _____.
are all Rr
In the essay, the point is made that perhaps the environment of the children has already guided their preferences in toys BEFORE the experiment was conducted. Given the choices below, what is the earliest age at which environment could potentially shape the preferences of a child?
at age 3 or 4, when children are dressed in gender-specific clothing
Based on the inheritance pattern, which mode of inheritance must be the cause of galactosemia?
autosomal recessive
Human populations in low-UV environments tend to have more lightly pigmented skin. One explanation is that the selective pressure for dark skin decreases as UV intensity decreases. At the same time there is selection for lighter skin to absorb more UV radiation, which is needed for vitamin D production.What evidence supports the vitamin D hypothesis for the evolution of lighter skin tones?
indigenous peoples living at high latitudes have darker skin, but they eat foods rich in vitamin D
The allele that causes cystic fibrosis is recessive. An individual who is heterozygous for cystic fibrosis
is a carrier
Suppose that the botanist carried out the test cross described in Parts A and B and determined that the original green-pod plant was heterozygous (Gg). Which of Mendel's findings does her test cross illustrate?
law of segregation
If Jane and John want to have another child, they plan to see a genetic counselor to find out when it would be best to test for galactosemia. A newborn with galactosemia must be put on a lactose- and galactose-free diet as soon as possible after birth. Even on this diet, affected individuals may still suffer from learning disabilities, ovarian failure (in young women), late-onset cataracts, and early death. Which of the following tests would be most useful for Jane and John to have?
newborn screening (either assaying for the GALT enzyme or measuring excess galactose in the newborn's blood)
Which of the following is LEAST likely to be a health problem for someone with cystic fibrosis?
obesity
If someone is a carrier of a recessive genetic disorder, it means he or she has __________ of the allele, and __________ exhibit symptoms of the disorder.
one copy; does not
The result of the following cross indicates the orange eyes are _____ black eyes.
recessive to
The result of the following cross indicates that the genotype of the male parent is _____.
rr
Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest about the trait?
that the parents were both heterozygous for a single trait
Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?
the melanin in darkly pigmented skin protects circulating folate from being destroyed by UV radiation, and folate is important in human reproduction
Why is this research on the zebrafish golden gene important for understanding human biology? Select all that apply.Hint: Read the Editor's introduction, the Abstract, and the first two paragraphs of the paper. The introductory paragraphs of a scientific paper typically provide information about the background, context, or significance of the work to be discussed.
the phenotype that results from having 3 dark-skin alleles
In certain plants, the tall trait is dominant to the short trait. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
0
What is the probability that F2 offspring will be AaBBCCdd?
1/128
What is the probability that F2 offspring will be AaBbCcDd?
1/16
A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits. Remember that extra digits is a dominant trait. Part A What fraction of this couple's children would be expected to have extra digits? Express your answer using the slash symbol and no spaces (for example, 1/16).
1/2
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?
1/2
Assuming independent assortment of these four genes, what is the probability that F2 offspring will be aabbccdd? Express your answer as a fraction using the slash symbol and no spaces (for example, 1/16).
1/256
What is the probability that F2 offspring will be AABBCCDD?
1/256
Imagine that you are a genetic counselor, and a couple planning to start a family comes to you for information. Charles was married once before, and he and his first wife had a child with cystic fibrosis. The brother of his current wife, Elaine, died of cystic fibrosis. Neither Charles, Elaine, nor their parents have cystic fibrosis. Part A What is the probability that Charles and Elaine will have a baby with cystic fibrosis? Express your answer as a fraction using the slash symbol and no spaces (for example, 1/16).
1/6
In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?
1/64
What is the probability that F2 offspring will be AaBBccDd?
1/64
What is the probability that all three children have the disease?
1/64
Keisha and Jerome each have a sibling with sickle-cell disease. Neither Keisha nor Jerome nor their parents have the disease, and none of them have ever been tested to see if they carry the sickle-cell allele. Part A Based on this incomplete information, calculate the probability that if this couple has a child, the child will have sickle-cell disease. Express your answer as a fraction (for example, 3/16).
1/9
What percentage of cross-eyed tigers will be white? Express your answer using the percent symbol and no spaces (for example, 10%).
100%
What will be the phenotypic ratio of the offspring?____ colorless: ____ purple: ____ red Express your answer as three whole numbers separated by colons (for example, 5:2:1).
12:3:1
Two true-breeding stocks of pea plants are crossed. One parent has red axial flowers, and the other has white terminal flowers; all F1 individuals have red axial flowers. The genes for flower color and location assort independently. If 1,000 F2 offspring resulted from the cross, approximately how many of them would you expect to have red terminal flowers?
190
f two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring will be cross-eyed? Express your answer using the percent symbol and no spaces (for example, 10%).
25%
If a woman and her husband, who are both carriers, have three children, what is the probability that all three children have the normal phenotype? Express your answer as a fraction using the slash symbol and no spaces (for example, 1/16).
27/64
Two true-breeding stocks of pea plants are crossed. One parent has red axial flowers, and the other has white terminal flowers; all F1 individuals have red axial flowers. The genes for flower color and location assort independently. Among the F2 offspring, what is the probability of plants with white axial flowers?
3/16
What is the probability that one or more of the three children have the disease?
37/64
The figure above shows a pedigree chart for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.What is the likelihood that the offspring of IV-3 and IV-4 will have the trait?
50%
What is the probability that at least one child is phenotypically normal?
63/64
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. True-breeding red-flowered long radishes are crossed with true-breeding white-flowered radishes. All of the F1 offspring are purple-flowered and long radishes. In the F2 generation of this cross, which of the following phenotypic ratios would be expected?
6:3:3:2:1:1
Tallness (T) in snapdragon plants is dominant to dwarfness (t), and red (CR) flower color is not dominant to white (CW). The heterozygous condition results in pink (CRCW) flower color. If snapdragons are heterozygous for height as well as for flower color, a mating between them will result in what ratio?
6:3:3:2:1:1
Determine the phenotypic ratios of the offspring.
9 green-inflated : 3 green-constricted : 3 yellow-inflated : 1 yellow-constricted
If plants heterozygous at both loci are crossed, what will be the genotypic ratio of the offspring?____ I - P - : ____ I - pp : ____ iiP - : ____ iipp Express your answer as four whole numbers separated by colons (for example, 5:3:2:1).
9:3:3:1
Why?
As people get older, they are more likely to exhibit symptoms of late-onset diseases. Therefore, less people will have children carrying lethal alleles for genetic disorders.
Suppose allele CVCV determines vertical "shirt-stripping", allele CHCH determines horizontal "shirt-stripping". Then, the genotype of father would be
CHCH
and the genotype of the son would be
CVCH
the genotype of mother would be
CVCV
Which of the following calculations described in the following statements require that you use the addition rule?
Calculate the probability of a child having only sickle-cell anemia or cystic fibrosis if each parent is each heterozygous for both traits.
The frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following concepts?
Darwin's explanation of natural selection
A scientist discovers a DNA-based test for one allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Which of the following statements describes the best use of this discovery?
Design a test for identifying heterozygous carriers of the allele.
Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. These results indicate which of the following about the inheritance pattern of fur color in Labrador retrievers?
Epistasis is involved.
The figure above represents a pedigree for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individuals' age at the time of diagnosis. A slash through the symbol indicates that the individual is deceased. In each generation of this family after generation I, the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic) cases of this cancer (~63 years). What is the most likely reason?
Hereditary (or familial) cases of this cancer typically occur at earlier ages than do nonfamilial forms.
What is the genotype of the man?
I A i
What is the genotype of the woman?
I B i
The figure above represents a pedigree for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individuals' age at the time of diagnosis. A slash through the symbol indicates that the individual is deceased. The affected woman in generation IV is thinking about her future and asks her oncologist (cancer specialist) whether she can know if any or all of her children will have a high risk of the same cancer. The doctor would be expected to advise which of the following: (I) genetic counseling; (II) prenatal diagnosis when/if she becomes pregnant; (III) testing to see whether she has the allele; (IV) testing to see whether her future spouse or partner has the allele?
I: genetic counseling only
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible partial genotype for the mother?
IAi
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible genotype for the son?
IBi
Which of the following statements correctly describes an example of epistasis?
In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing.
How would you determine whether the curl allele is dominant or recessive?
Matings of the original mutant cat with true-breeding noncurl cats will produce both curl and noncurl F1F1 offspring if the curl allele is dominant, but only noncurl offspring if the curl allele is recess
What genotypes are possible for each of the other individuals?
Sandra, Tina, and Christopher can each have either the AA or Aa genotype
What effects might this trend have on the incidence (frequency) of late-acting dominant lethal alleles in the population?
The frequency of late-acting dominant lethal alleles will decrease faster than before.
In what frequencies would you expect the offspring genotypes? Indicate the frequency of each genotype by dragging the labels to the table. Labels may be used once, more than once, or not at all.
all are 1/4
Drosophila (fruit flies) usually have long wings (+ is the symbol used to represent this allele), but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). In symbolizing fruit fly alleles, it is common to use two letters as opposed to only one. If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect?
all btvg heterozygotes, long-winged flies
Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus homozygous for dull spines would produce
all sharp-spined progeny.
It is an example of
codominance
Which of the following experiments would provide the best data for determining the effect of genetics?
comparing identical twins raised in the same environment with fraternal twins raised in the same environment
What is the genotype of the child?
ii
What genotypes would you expect in future offspring from this marriage? Select all that apply.
ii I A i I B i I A I B
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. True-breeding red-flowered long radishes are crossed with true-breeding white-flowered radishes. All of the F1 offspring are purple-flowered and long radishes. The flower color trait in radishes is an example of which of the following types of inheritance?
incomplete dominance
Drag the appropriate labels to their respective targets. Reset Help
otp
Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this expression of phenotypes?
pleiotropy
Which of the following describes the ability of a single gene to have multiple phenotypic effects?
pleiotropy
Skin color in humans has a wide variety of phenotypes. The expression of this trait is caused by more than two genes. What type of inheritance pattern is responsible for this expression?
polygenic inheritance
Does alkaptonuria appear to be caused by a dominant allele or by a recessive allele?
recessive
The addition rule of probability can be defined as
the probability that either one of two mutually exclusive events will occur.
A tall, purple-flowered pea plant (TtPp) is allowed to self-pollinate. (The recessive alleles code for short plants and white flowers.) The phenotypic ratio of the resulting offspring is 9:3:3:1. What is the genotype of the plant whose phenotype appeared once out of every 16 offspring (the "1" in the 9:3:3:1 ratio)?
ttpp
In humans, wavy hair occurs in heterozygotes (HSHC) offspring of people with straight hair (HSHS) and curly hair (HCHC). Which of the following crosses would produce offspring with the ratio of 1 straight:2 wavy:1 curly?
wavy × wavy
In what way does natural selection depend on the specific environment in which an organism lives?
when the environment changes, traits that were beneficial to an organism may become harmful and vice versa.
The figure above shows a pedigree chart for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.What is the genotype of individual II-5?
ww
Labrador retrievers have black, brown, or yellow fur. Fur color is controlled by two genes, one of which exhibits epistasis. Black (B) is dominant over brown (b) in one gene, and (E) is dominant over (e) in the other gene. The (E) gene is epistatic to the (B) gene. In a cross of a black female with a brown male, results can be all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. In one cross of black × black, the results were as follows: 9/16 black, 4/16 yellow, 3/16 brown. The genotype eebb must result in which of the following?
yellow
Tallness (T) in snapdragon plants is dominant to dwarfness (t), and red (CR) flower color is not dominant to white (CW). The heterozygous condition results in pink (CRCW) flower color. A dwarf red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F1 individuals?
−− TtCRCW , tall and pink
If B represents the allele for black eyes (dominant) and b represents the allele for orange eyes (recessive), what would be the genotypic ratio of a cross between a heterozygous black-eyed MendAlien and an orange-eyed MendAlien?
0 homozygous black (BB): 1 heterozygote (black) (Bb): 1 homozygous orange (bb
If Sophie conceives a child, and the father neither has cystic fibrosis nor is a carrier, what are the chances that the child would have cystic fibrosis?
0%
How many variables should there be in a well-designed experiment?
1
What is the probability that this pair would produce the indicated offspring? (Assume independent assortment of all gene pairs.) AABBCC ×× aabbcc →→ AaBbCc Express your answer as a fraction using the slash symbol and no spaces (for example, 1/16).
1
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one D allele have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure above, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the boxes marked 1−−4 correspond(s) to plants with dark leaves?
1, 2, and 3
What is the probability that this pair would produce the indicated offspring? (Assume independent assortment of all gene pairs.) AABbCc ×× AaBbCc →→ AAbbCC
1/32
What proportion of the offspring would you expect to be homozygous for axial and tall, and heterozygous for seed shape?
1/32
Which of the following statements correctly describes a dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters.
Which of the following statements correctly describes a monohybrid cross?
A monohybrid cross involves organisms that are heterozygous for one character. SubmitP
Which of these is a testcross?
A? x aa
Which of the following statements accurately describes melanin's function?
Lighter skin has less of the dark-brown eumelanin that protects cells from UV damage.
A BbGg x bbgg cross yields a phenotypic ratio of approximately 5 black eyes, green skin : 5 orange eyes, white skin : 1 black eyes, white skin : 1 orange eyes, green skin. Which of the following best explains these results?
Mendel's law of independent assortment is being violated.
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one D allele have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure above, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the plants will be true-breeding?
1 and 4
If B represents the allele for black eyes (dominant) and b represents the allele for orange eyes (recessive), what would be the phenotypic ratio of a cross between a heterozygous black-eyed MendAlien and an orange-eyed MendAlien?
1 black : 1 orange
Black eyes are dominant to orange eyes, and green skin is dominant to white skin. Sam, a MendAlien with black eyes and green skin, has a parent with orange eyes and white skin. Carole is a MendAlien with orange eyes and white skin. If Sam and Carole were to mate, the predicted phenotypic ratio of their offspring would be _____.
1 black eyes, green skin : 1 black eyes, white skin : 1 orange eyes, green skin : 1 orange eyes, white skin
An individual heterozygous for eye color, skin color, and number of eyes mates with an individual who is homozygous recessive for all three characters; what would be the expected phenotypic ratio of their offspring? [Hint: B = black eyes, b = orange eyes; G = green skin, g = white skin; C = two eyes, c = one eye]
1 black eyes, green skin, two eyes : 1 black eyes, green skin, one eye : 1 black eyes, white skin, two eyes : 1 black eyes, white skin, one eye : 1 orange eyes, green skin, two eyes : 1 orange eyes, green skin, one eye : 1 orange eyes, white skin, two eyes : 1 orange eyes, white skin, one eye
What is the probability that this pair would produce the indicated offspring? (Assume independent assortment of all gene pairs.) AaBbCc ×× AaBbCc →→ AaBbCc
1/8
In addition to A and a, the "agouti" gene has a third allele, AY . Here is some information about the inheritance of the AY allele. The AY allele is dominant to both A and a. The homozygous genotype (AYAY ) results in lethality before birth. The heterozygous genotypes (AYA or AYa) result in yellow fur color, regardless of which alleles are present for the B/b gene. (This effect exhibited by the AY allele is known as epistasis--when the expression of one gene masks the expression of a second gene.)
2/3
Two mice are heterozygous for albinism (Aa) . The dominant allele (A) codes for normal pigmentation, and the recessive allele (a) codes for no pigmentation. What percentage of their offspring would have an albino phenotype?
25
In the same mouse species, a fourth unlinked gene (gene P/p) also affects fur color. For mice that are either homozygous dominant (PP) or heterozygous (Pp), the organism's fur color is dictated by the other three genes (A/a, B/b, and C/c). For mice that are homozygous recessive (pp), large patches of the organism's fur are white. This condition is called piebaldism. In a cross between two mice that are heterozygous for agouti, black, color, and piebaldism, what is the probability that offspring will have solid black fur along with large patches of white fur? (Hint: Consider each gene separately; then use the multiplication rule. For more help getting started, see Hint 1.)
9/256
What does this example indicate about the distribution of phenotype frequencies in a population?
A lethal combination of alleles in a population will result in phenotype frequencies that do not have a normal distribution.
In the following cross the genotype of the female parent is BbGg. What is the genotype of the male parent? [Hint: B = black eyes, b = orange eyes, G = green skin, g = white skin]
BBGg
The observed distribution of alleles into gametes is an illustration of _____.
Mendel's laws of segregation and independent assortment
If an organism with the genotype AaBb produces gametes, what proportion of the gametes would be Bb?
None
Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
One allele was dominant.
Why is this research on the zebrafish golden gene important for understanding human biology? Select all that apply.Hint: Read the Editor's introduction, the Abstract, and the first two paragraphs of the paper. The introductory paragraphs of a scientific paper typically provide information about the background, context, or significance of the work to be discussed.
This research revealed that the gene SLC24A5 influences production of the pigment melanin. We now know that humans have a gene with similar sequence and function to a zebrafish gene that explains 25% of the difference in skin color between European and African populations. This research underscores the fact that all humans are very similar genetically, and differences in features like skin color are due to natural selection favoring small genetic changes in different environments.
True or false? The same phenotype can be produced by more than one genotype.
True
Can you match these prefixes, suffixes, and word roots with their definitions?
against: anti- of neither gender or type: neutr- change, turn, move: trop- (or -tropic) not: non- from, out of, remove: de- many: poly- difficult, painful: dys- to love: -phil (or philo-) to: ad- with or together with: co-
In order to determine the genotype of a MendAlien with black eyes and green skin, you would cross this individual with a(n) _____ individual.
bbgg
Based on the risk factors discussed in the video, which of the following groups would be most likely to develop the bone disease rickets?
children born to parents with dark skin living far from the equator
Which of the following experiments would provide the best data for determining the effect of environment?
comparing identical twins raised in the same environment with identical twins raised in different environments
Theoretically, which of the following diseases should be the easiest to treat through gene therapy, considering the targeted organs and tissues where the corrected gene must be delivered? Theoretically
diabetes, since the target cells are found only in the pancreas
Which of the following statements describes the major reason that an individual with the genotype AaBbCCDdEE can make many kinds of gametes?
different possible assortment of chromosomes into gametes
A cross between an individual with orange eyes and green skin and an individual with black eyes and white skin is an example of a _____ cross.
dihybrid
Consider pea plants with the genotypes GgTt and ggtt. How many types of gametes can be produced by each of these two plants?
four...one
When constructing a Punnett square, the symbols on the outside of the boxes represent _______, while those inside the boxes represent _______.
gametes, progeny