Genetics Exam 2 Flashcards
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Questions and Answers

All genes on the same chromosome are genetically linked?

False

What is the distance between the color gene locus and the feather gene locus?

  • 50 map units
  • 10 map units (correct)
  • 100 map units
  • 20 map units
  • 5 map units

    • Which of these options are correct? (Select all that apply)

  • 0.5
  • 0.9
  • 0.1
  • 0.01 (correct)
  • 0.1
  • 0.99

    • Rare alleles are always recessive.

    <p>False</p> Signup and view all the answers

    What is the probability that a child has sickle-cell disease when one parent is a carrier and the other is normal?

    <p>0%</p> Signup and view all the answers

    What type of cross will help you determine the genotype of a tall plant with yellow seeds? (Choose all that apply)

    <p>Crossing it with a short/green plant</p> Signup and view all the answers

    What is this an example of: A true breeding red carnation crossed with a true breeding white carnation produces pink progeny? (Choose one)

    <p>Incomplete dominance</p> Signup and view all the answers

    If your P value = 0.1 in a chi-squared test, what can you conclude?

    <p>You cannot reject your null hypothesis</p> Signup and view all the answers

    Which pattern of inheritance best describes the disease associated with the following pedigree?

    <p>Autosomal recessive</p> Signup and view all the answers

    Which of the following are true statements regarding sex-linked genes? (Choose all that apply)

    <p>Sex-linked genes are genes that are located on sex chromosomes.</p> Signup and view all the answers

    What is the probability that the daughter of a homozygous normal woman and a color blind man is color blind? (Choose one)

    <p>0%</p> Signup and view all the answers

    How many different offspring genotypes and phenotypes are expected from a cross between F1 parents heterozygous for three traits?

    <p>27 genotypes; 8 phenotypes</p> Signup and view all the answers

    In a cross between two heterozygous plants for flower color (W), what is the genotypic ratio of the offspring? (Choose one)

    <p>1:2:1</p> Signup and view all the answers

    Which of the following genotypes would not usually be represented in a gamete? (Choose all that apply)

    <p>aa</p> Signup and view all the answers

    What is the probability that individual #7 will be affected by the disease in a pedigree where individual #1 is a heterozygote?

    <p>0.016</p> Signup and view all the answers

    What will be the phenotype of an individual with the genotype aabbDD?

    <p>colorless</p> Signup and view all the answers

    If the results of a chi-square test show a P value greater than 0.05, then the null hypothesis... (Choose one)

    <p>cannot be rejected.</p> Signup and view all the answers

    In a dihybrid cross yielding 320 F2 offspring, how many are expected to resemble the homozygous recessive parental? (Choose one)

    <p>20</p> Signup and view all the answers

    What will be the phenotypic ratios among the offspring of a cross AabbDd x AaBbdd?

    <p>7 red: 7 blue: 2 colorless</p> Signup and view all the answers

    Which of the following genotypes can be conclusively considered the recombinant progeny?

    <p>ccEe</p> Signup and view all the answers

    Which of the following crosses would produce a 1:1 ratio of phenotypes in the next generation? (Choose one)

    <p>Aa x aa</p> Signup and view all the answers

    If you crossed a pure-breeding constricted plant with a pure-breeding inflated plant, and found that in F2 progeny there were 650 inflated-pod plants, approximately how many constricted-pod plants would you expect? (Choose one)

    <p>217</p> Signup and view all the answers

    If the pedigree is for an autosomal recessive characteristic, which individuals are definitely heterozygous?

    <p>I-1</p> Signup and view all the answers

    Assuming no linkage between genes A and B in a cross of AABB x aabb, what will be the proportions of the gametes produced by the F1? (Choose one)

    <p>1:1:1:1</p> Signup and view all the answers

    What is the map distance between genes B and C in the beetle?

    <p>4 m.u.</p> Signup and view all the answers

    What is the mode of inheritance of the beard trait in goats that is dominant in males and recessive in females? (Choose one)

    <p>Sex-influenced</p> Signup and view all the answers

    If two true-breeding mutant strains of Drosophila have wild-type offspring, how can these data be interpreted?

    <p>The mutations involved are on two different genes.</p> Signup and view all the answers

    In the yawncat, what is the best explanation for the inheritance of tail phenotypes?

    <p>The Manx phenotype is dominant, but the allele is a recessive lethal.</p> Signup and view all the answers

    What can you conclude about the genotype of the mother if a man with albinism and a normal woman have a child with albinism?

    <p>The mother must be heterozygous (a carrier).</p> Signup and view all the answers

    What is the expected frequency of short white-flowered plants in the F2 generation?

    <p>0.01</p> Signup and view all the answers

    What is the probability that the children who do not display albinism are heterozygous?

    <p>100%</p> Signup and view all the answers

    In snapdragons, the inheritance pattern that exhibits an intermediate phenotype in offspring is called? (Choose one)

    <p>incomplete dominance</p> Signup and view all the answers

    What is the Chi-Squared value?

    <p>7.94</p> Signup and view all the answers

    If two Manx cats are bred together, what is the chance that a kitten will have a tail?

    <p>1/3</p> Signup and view all the answers

    Consider a gene encoding for a transcription factor important in promoting gene expression. Would you expect a loss-of-function allele of this gene to be dominant, recessive or neither to the normal allele?

    <p>Recessive, because the regulated gene would still be turned on by the product of the normal allele.</p> Signup and view all the answers

    Explain why a heterozygous wild flower produces blue petals, similar to that seen in the W+W+ wild flower.

    <p>Because half as much gene product is enough to produce the normal amount of pigment.</p> Signup and view all the answers

    Which of these statements is/are true about a dominant/recessive allele pair?

    <p>The dominant allele's effect is the only one seen in the heterozygote.</p> Signup and view all the answers

    What color will a ripe Rr cc XX pepper be?

    <p>Orange</p> Signup and view all the answers

    What color will a ripe rr CC Xx pepper be?

    <p>Yellow</p> Signup and view all the answers

    Which of these genotypes could a brown pepper have?

    <p>Rr CC xx</p> Signup and view all the answers

    What gametes will many meioses produce from a man with genotype A1A2, and in what proportions?

    <p>½ A1, ½ A2</p> Signup and view all the answers

    What gametes will many meioses produce from a man with genotype A1A1 G1G2, and in what proportions?

    <p>½ A1G1, ½ A1G2</p> Signup and view all the answers

    Which underlined word makes this sentence incorrect? - During meiosis I each pair of homologous chromosomes is pulled apart by the spindle fibers attached to their cohesin, and cell division produces two haploid cells.

    <p>Cohesin</p> Signup and view all the answers

    Which word should replace the incorrect word in the statement? - During meiosis I each pair of homologous chromosomes is pulled apart by the spindle fibers attached to their cohesin, and cell division produces two haploid cells.

    <p>Kinetochores</p> Signup and view all the answers

    How many different combinations of chromosomes are possible in the gametes of a single person?

    <p>2^23</p> Signup and view all the answers

    What gamete genotypes could result from crossovers at position 2 and position 3?

    <p>C2A2B2</p> Signup and view all the answers

    How frequent are embryos containing only wildtype alleles expected to be?

    <p>25%</p> Signup and view all the answers

    If a diploid cell contains 8 chromosomes (2n = 8), how many different combinations in the gametes are possible?

    <p>16</p> Signup and view all the answers

    What is the total number of telomeres in a rat cell in G2 if the somatic cell has 42 chromosomes?

    <p>168</p> Signup and view all the answers

    What is the total number of chromosomes in a polar body cell from a rat if the somatic cell has 42 chromosomes?

    <p>21</p> Signup and view all the answers

    What is the total number of chromosomes present in the cell during metaphase I of meiosis in a rat with 42 chromosomes?

    <p>42</p> Signup and view all the answers

    Explain why the deletion mutation in CFTR gene is more severe than the point mutation.

    <p>The deletion prevents protein from functioning properly, while the point mutation allows some functionality.</p> Signup and view all the answers

    Describe the purpose of mitosis and meiosis.

    <p>Mitosis produces two identical daughter cells, meiosis produces gametes with half the chromosome number.</p> Signup and view all the answers

    What are the expected chromosome and DNA molecule counts as a cell progresses through various stages, starting from G1 with 8 chromosomes?

    <p>G1: 8 chromosomes, 8 DNA molecules; G2: 8 chromosomes, 16 DNA molecules; Metaphase of Mitosis: 8 chromosomes, 16 DNA molecules; Anaphase of Mitosis: 16 chromosomes, 16 DNA molecules; After Cytokinesis: 8 chromosomes, 8 DNA molecules; Metaphase I: 8 chromosomes, 16 DNA molecules; Metaphase II: 4 chromosomes, 8 DNA molecules; After Cytokinesis II: 4 chromosomes, 4 DNA molecules.</p> Signup and view all the answers

    Which of the following traits concerning Mendel's observations is correct?

    <p>Yellow color is dominant to green.</p> Signup and view all the answers

    A cell that just replicated its genome in S-phase went from a haploid to a diploid state.

    <p>False</p> Signup and view all the answers

    What is the genotype of one of the daughter cells produced by a cell with genotype AaBb during mitosis?

    <p>AaBb</p> Signup and view all the answers

    What is the genotype of one of the gametes produced by a cell with genotype AABB during meiosis?

    <p>AB</p> Signup and view all the answers

    Which statements about mitosis and meiosis are true?

    <p>Sister chromatids separate during mitosis and meiosis II.</p> Signup and view all the answers

    Which factors play an important role in generating genetic diversity?

    <p>Sexual Reproduction</p> Signup and view all the answers

    Which factors contributed to Mendel's success in genetics?

    <p>His understanding and application of statistics.</p> Signup and view all the answers

    Which principle of genetics was not concluded by Mendel?

    <p>The Law of Linked Genes</p> Signup and view all the answers

    Which of the following does not follow basic Mendelian Patterns of Inheritance?

    <p>A red flowered plant crossed with a white flowered plant produce only pink flowered plants.</p> Signup and view all the answers

    If a homozygous black-furred Ewok has a cub with a brown-furred Ewok, what is the chance that the cub is brown-furred?

    <p>0%</p> Signup and view all the answers

    You cross a yellow round (genotype YYRr) with a green wrinkled plant (genotype yyrr). What percent of the progeny will be green wrinkled?

    <p>0%</p> Signup and view all the answers

    Which p-value would indicate that you reject the null hypothesis in a chi-squared analysis?

    <p>A p-value less than 0.05 indicates that you would reject the null hypothesis.</p> Signup and view all the answers

    Which of these options are correct? (Select all that apply)

    <p>0.01</p> Signup and view all the answers

    What type of cross will help determine the genotype of a tall plant with yellow seeds? (Select all that apply)

    <p>A test cross</p> Signup and view all the answers

    What does the crossing of a true breeding red carnation with a true breeding white carnation and producing progeny that are pink demonstrate?

    <p>Incomplete dominance</p> Signup and view all the answers

    Which of the following are true statements regarding sex-linked genes? (Select all that apply)

    <p>The probability of expressing a sex-linked trait is different between males and females.</p> Signup and view all the answers

    What is the probability that the daughter of a homozygous normal woman and a color blind man is color blind?

    <p>0%</p> Signup and view all the answers

    If two heterozygous plants for flower color in lilies are mated, what would the genotypic ratio of the offspring be?

    <p>1:2:1</p> Signup and view all the answers

    Which of the following genotypes would not usually be represented in a gamete? (Select all that apply)

    <p>bb</p> Signup and view all the answers

    If the results of a chi-square test show a P value greater than 0.05, what can be said about the null hypothesis?

    <p>Cannot be rejected.</p> Signup and view all the answers

    How many offspring resembling the homozygous recessive parental are expected in a dihybrid cross yielding 320 F2 offspring?

    <p>20</p> Signup and view all the answers

    Which of the following crosses would produce a 1:1 ratio of phenotypes in the next generation?

    <p>Aa x aa</p> Signup and view all the answers

    How many constricted-pod plants would you expect from a cross between a pure-breeding constricted plant and a pure-breeding inflated plant if 650 inflated-pod plants were produced?

    <p>217</p> Signup and view all the answers

    What will be the proportions of the gametes produced by a cross of AABB x aabb?

    <p>1:1:1:1</p> Signup and view all the answers

    Which genotype could a black, solid female dog have?

    <p>BBSs</p> Signup and view all the answers

    What inheritance pattern best explains the given pedigree?

    <p>Y-linked</p> Signup and view all the answers

    Which statement explains Mendel's conclusion that parent plants contribute equally to 'genetic factors'?

    <p>The pollen and egg each have one haploid set of chromosomes.</p> Signup and view all the answers

    Which situations describe genes that do not assort independently? (Select all that apply)

    <p>The two loci are close together on the same chromosome.</p> Signup and view all the answers

    What is the expected phenotypic ratio if a cross of Cc x chc is made, where C is full color and ch is Himalayan?

    <p>2 full color:1 Himalayan:1 albino</p> Signup and view all the answers

    The likelihood of a recombination event between closely linked genes is:

    <p>The less likely there will be a recombination event between them.</p> Signup and view all the answers

    What is the probability that the first child of a woman with normal vision (whose maternal grandfather had red-green colorblindness) and a man with normal vision (whose father was colorblind) is color blind?

    <p>1/8</p> Signup and view all the answers

    What can you conclude about the genotype of the mother with albinism offspring?

    <p>The mother must be heterozygous (a carrier).</p> Signup and view all the answers

    What is the probability that the children who do not display albinism are heterozygous?

    <p>100%</p> Signup and view all the answers

    Explain and differentiate among codominance, incomplete dominance, and complete dominance.

    <p>In codominance, both allelic phenotypes are expressed. In incomplete dominance, a heterozygote displays an intermediate phenotype. In complete dominance, one dominant allele masks the expression of the recessive allele.</p> Signup and view all the answers

    In chickens, what is the mode of inheritance of 'frizzle'?

    <p>Incomplete dominance</p> Signup and view all the answers

    Which of the following represents the presence of a beard on some goats?

    <p>Sex-influenced</p> Signup and view all the answers

    What is the probability of the next offspring from a mating between a solid yellow-tailed male and a solid brown-tailed female yawncat having a spotted brown tail?

    <p>1/16</p> Signup and view all the answers

    Which phenomenon explains the purple F1 offspring among the true-breeding white mutants?

    <p>Complementation</p> Signup and view all the answers

    If genes A and B are closely linked, what is the likelihood that the son of a man with genotype AaBb and a homozygous recessive woman is homozygous recessive like his mother?

    <p>25%</p> Signup and view all the answers

    What type of cross can determine recombination frequencies between two linked traits?

    <p>A test cross</p> Signup and view all the answers

    You can calculate the genetic distance of two genes in map units if you know the distance between the genes in base pairs.

    <p>False</p> Signup and view all the answers

    Study Notes

    Genetics and Inheritance Patterns

    • Dominance in alleles can be recessive (regulation still possible with normal allele) or dominant (absence of function seen).
    • Heterozygous alleles can display dominant phenotypes even if one is defective due to sufficient gene product.

    Genetic Traits and Expression

    • Gene interactions can lead to various phenotypes based on dominant and recessive alleles; for example, the interaction of the R and C genes affects bell pepper color, creating potential for multiple pigment combinations (red, yellow, brown, orange).
    • The presence of certain alleles can mask or enhance phenotypic expression, leading to different appearances despite genetic variations.

    Gamete Formation and Meiosis

    • Gametes from genotypes with different alleles display varied proportions (e.g., A1A2 produces 50% A1 and 50% A2).
    • Meiosis generates gametes that can exhibit various allele combinations due to independent assortment and crossing over.

    Genetic Probability and Ratios

    • Genetic probabilities in offspring can be determined through Punnett squares, identifying ratios for traits based on parental genotypes (e.g., a test cross can identify unknown genotypes).
    • For traits governed by incomplete dominance, offspring ratios may differ from simple Mendelian ratios, such as a 1:2:1 ratio in pink-red-white floral color crosses.

    Key Concepts in Mitosis and Meiosis

    • Mitosis maintains ploidy by duplicating chromosomes but meiosis reduces ploidy, critical for sexual reproduction diversity.
    • The separation of sister chromatids occurs in both mitosis and meiosis II, while homologous chromosome separation happens in meiosis I.

    Genetic Diversity Mechanisms

    • Variability in genetics arises from mechanisms like random fertilization, independent assortment during meiosis, and recombination.
    • Genetic variation is essential in populations, leading to evolutionary advantages.

    Mendelian Genetics Insights

    • Mendel's principles highlight the significance of statistics, careful observation, and appropriate organism selection in studying inheritance.
    • Certain genetic principles, such as the Law of Linked Genes, were not established by Mendel; he focused on independent assortment and segregation.

    Inheritance of Sex-Linked Traits

    • Traits linked to sex chromosomes exhibit different expression probabilities between genders; for example, male and female expression rates can drastically differ for sex-linked conditions like color blindness.

    Genetic Testing and Analysis

    • Chi-squared tests can help determine if observed data fit expected Mendelian ratios, guiding conclusions about genetic inheritance patterns.
    • Understanding ratios, probabilities, and interactions is crucial for genetics studies, especially when exploring familial traits or disorders.### Genetic Concepts and Punnett Squares
    • Certain genotypes, such as aa, BB, AA, bb, Bb, and Aa, are typically not represented in gametes due to homozygosity or specific genetic expressions.
    • A chi-square test result with a P value greater than 0.05 indicates that the null hypothesis cannot be rejected, suggesting no significant difference in the observed data.
    • In a dihybrid cross yielding 320 F2 offspring, 20 are expected to resemble the homozygous recessive parental phenotype.

    Mendelian Ratios and Crosses

    • A cross of Aa x aa produces a 1:1 ratio of phenotypes in the offspring.
    • Among offspring from a pure-breeding constricted plant crossed with a pure-breeding inflated plant, approximately 217 are expected to have the recessive constricted phenotype.
    • For a cross AABB x aabb, the F1 generation produces gametes in a 1:1:1:1 ratio.

    Traits and Inheritance Patterns

    • Genetic traits in dogs, like coat color, exhibit dominance where black (B) is dominant over brown (b), and solid (S) is dominant over spotted (s).
    • The inheritance pattern for certain traits can be classified as Y-linked, autosomal dominant, or recessive depending on the pedigree analysis.
    • Mendel’s conclusion about genetic factors being equally contributed by both parents relates to the haploidy of gametes.

    Epistasis and Gene Interaction

    • Epistasis can occur in traits determined by multiple genes, where one gene can mask the expression of another, such as with coat color in Labrador retrievers.
    • The presence of a secondary locus that affects the expression of primary alleles exemplifies recessive epistasis if the recessive form of one gene masks the effect of dominant forms of others.

    Probability in Genetic Outcomes

    • Probability calculations in genetic crosses indicate that complex traits undergo multiple allele interactions, influencing the expected ratios of phenotypes.
    • The chance of producing specific offspring can be calculated using principles of Mendelian genetics, requiring knowledge of dominant and recessive traits.

    Pedigree Analysis

    • An affected male is represented by a shaded square in pedigree charts.
    • Dominance or recessiveness of traits can often be inferred from the patterns of inheritance observable within pedigree diagrams.

    Traits and Penetrance

    • Penetrance describes the percentage of individuals with a given genotype who exhibit the associated phenotype, such as 60% for a certain dominant trait.
    • Variable expressivity showcases the influence of environmental factors or genetic interactions on the manifestation of a trait's phenotype.

    Map Units and Recombination

    • Genetic distance between loci is defined by recombination frequencies; closer genes exhibit reduced likelihood of recombination.
    • Test crosses are ideal for determining genetic distances through observation of offspring ratios, confirming whether traits assort independently.

    Inheritance Variations

    • Define modes of inheritance such as sex-influenced and sex-limited traits, which demonstrate differing patterns of expression in males and females.
    • Examine examples of incomplete dominance where a heterozygote expresses an intermediate phenotype between two homozygous forms, indicating complexity in phenotype predictions.

    Conclusion

    • Understanding the fundamentals of genetic inheritance, including Punnett squares, gene interactions, probability, and phenotype expression, is essential for predicting and analyzing genetic outcomes in various organisms.### Recombinant Progeny Genotypes
    • Recombinant progeny result from a crossover event between homologous chromosomes during meiosis.
    • Genotypes considered recombinant: ccEe and Ccee.

    Heterozygous Individuals in Autosomal Recessive Traits

    • For autosomal recessive traits, individuals that are heterozygous can be identified based on the presence of recessive phenotypes in offspring.
    • Confirmed heterozygous individuals: II-5, III-1, II-4, I-1, and I-2.

    Linkage and Genetic Mapping

    • Genes located on the same chromosome are subject to linkage and can be mapped based on recombination frequencies.
    • Given F2 phenotypes from a testcross involving body color and wing shape in beetles, the map distance is calculated as 4 m.u.
    • When two genes are 20 map units apart, expect a 0.01 probability of occurring together as short white-flowered plants.

    Inheritance Patterns in Mice

    • Tail size in mice shows a pattern where the short allele may be lethal when homozygous, resulting in unexpected ratios.
    • Best explanation for tail inheritance: one autosomal tail-length gene with two alleles, with lethal short allele.

    Complementation in Drosophila

    • Two true-breeding mutant Drosophila with different body color phenotypes can complement each other, indicating mutations on different genes.

    Gene Linkage Implications

    • In a test cross resulting in equal frequencies of progeny types, genes may be located on different chromosomes or far apart on the same chromosome.
    • Recombination frequency of 18% suggests a distance of 18 map units between genes.

    Manx Cats’ Tail Phenotype

    • The Manx phenotype shows a dominant-recessive relationship with a recessive lethal allele, explaining inheritance patterns.

    Oil Content in Diploid Grains

    • Oil content controlled by multiple genes can result in phenotypes based on additive effects, with specific genetic combinations leading to specific oil percentages.

    Yawncat Genetic Analysis

    • Complex inheritance involving three genes results in various tail phenotypes, with the female parent's most likely genotype being mm bb Rr.

    Chi-Squared Test in Tomato Genetics

    • Chi-squared value of 7.94 indicates linkage between two genes in a dihybrid cross, as the expected ratios differ significantly from observed ratios.

    Inheritance of Plant Height

    • Plant height is a trait of polygenic inheritance influenced by multiple gene pairs.
    • Parental genotypes were identified as aabbcc and AABBCC with the F1 being AaBbCc.
    • Phenotypic ratio from crossing a F1 with an extreme phenotype plant predicts a 1:3:3:1 ratio of plant heights.

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    This quiz covers key concepts from the Genetics Exam 2, focusing on gene function, alleles, and transcription factors. Test your understanding of allelic interactions and their effects on gene expression. Perfect for review before the exam.

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