3.5.1.3. Eye color (problems solved)

Autosomal dominant inheritance. Eye color (Page 4)

The color of the eyes is somewhat more complicated than what we are going to see here. It is not only determined by a single gene, but two are involved. The chromosome 15 with alleles M and m, where the presence, at the least, a M determines that the eyes are brown and the presence of the two eyes mm determines that are clear, blue or green. We, in the simulation, will stay here.

As we say, this type of inheritance is complicated because the other gene, on chromosome 19, will determine in people with light eyes (mm) whether the eyes will be blue or green . Individuals who already have M in the first gene will have brown eyes regardless of the combination in the second gene. Therefore, this second gene only influences the phenotype in individuals of genotype mm. It has two alleles, V and v, the green eye color being dominant. Thus, if we have at least one V ( VV or Vv ) in this gene, the eye color will be green, and if we have both vv alleles, the eye color will be blue..

As we have said, in the simulation we will see what the eyes of the descendants (brown or light) look like depending on the genotype of the parents.

Genetics problem 19

In humans, the brown color of the eyes (A) is dominant over the blue color (a). A brown-eyed man and a blue-eyed woman have two children, one with brown eyes and the other with blue eyes. Find out all the genotypes:

Genetics problem 20

The blue color of the eyes in men is due to a recessive gene with respect to its allele for the color brown. The parents of a blue-eyed male both have brown eyes. What are their genotypes?

Genetics problem 21

a) Olga and Juan, both with brown eyes, have a male child (Luis) with blue eyes. What type of inheritance occurs? Indicate the genotype of the three individuals.

b) Luis, the son of Olga and Juan, married María, with brown eyes, whose mother (Pilar) was blue-eyed and whose father was brown-eyed. Maria had a brother with blue eyes. Luis and María had a son (Álvaro), with brown eyes. Indicate the genotypes of all the characters in this question.

Genetics problem 22

In the human species the color of the eyes is determined by a pair of alleles. A blue-eyed man marries a brown-eyed woman. The woman's mother was blue-eyed and the father, who had a blue-eyed brother, was brown-eyed. From the marriage a son with brown eyes was born. Indicates the probability of having a child with blue eyes. The color of brown eyes dominates over that of blue eyes.

Genetics problem 23

In the human species, the color of the eyes is an autosomal character where the allele of the brown color "A" dominates over that of the blue color "a". A brown-eyed man, whose mother has blue eyes, has two descendants with a blue-eyed woman. What are the genotypes of men and women? And those of the descendants? What is the probability that this couple has descendants with blue eyes? And the probability of having descendants with brown eyes? Reason for the answers.

Genetics problem 24

In the human species, black eyes dominate over blue eyes. A black-eyed man is joined by a blue-eyed woman and they have a blue-eyed son.

What are the genotypes of the black-eyed man, the blue-eyed woman, and the blue-eyed son?
Give reasons for the answer.
Can this couple have a child with black eyes? Give reasons for the answer.

Genetics problem 25

We assume that eye color in humans is controlled by a gene with two alleles: -b- responsible for blue eyes and -B, which produces brown eyes and is dominant over -b-:

a) What is the genotype of a brown-eyed man who has a blue-eyed son with a blue-eyed woman? Reason for the answer;

b) Considering the same previous mating, what proportion of the two eye colors would be expected in the offspring?;

c) What proportion would be expected in terms of eye color in the progeny of a mating between two brown-eyed individuals, each of which had a parent with blue eyes? Represents mating;

d) Which of Mendel's laws is supposed to apply in the proposed crossing in the question? Reason for the answer.

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It is a problem in which only one character determined by two alleles appears, where B (brown eyes) dominates over b (blue eyes).

a) What is the genotype of a brown-eyed man who has a blue-eyed son with a blue-eyed woman

Parents B_ x bb

Gametes B _ b

Blue-eyed son bb.

For the son to have blue eyes bb, the father has to be Bb.

b) What proportion of the two eye colors would be expected in the descendants?;

Parents Bb x bb

Gametes B b b

Sons Bb bb

50% brown 50% blue

c) What proportion would be expected in terms of eye color in the progeny of a mating between two brown-eyed individuals, each of which had a parent with blue eyes?

If the brown-eyed (B_) individuals have a blue-eyed (bb) parent, the individuals must be Bb.

Parents Bb x Bb

Gametes B b B b

Sons BB Bb Bb bb

75% brown eyes 25% blue eyes

d) In this crossing, Mendel's 2nd law or segregation of the genes of each allele has been applied, the two alleles of the heterozygous separate when the gametes are formed.

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Skip navigation Biology and Geology 4th ESO Biology and Geology 4º ESO 1. The cell 1.1. Levels of organization of living beings 1.2. Cell theory 1.3. The cell 1.3.1. Prokaryotic cell 1.3.2. Eukaryotic cell 1.3.2.1. Common organelles 1.3.2.2. Organelles of the animal cell 1.3.2.3. Plant cell organelles 1.4. Cell nucleus 1.5. Vital functions of cells 1.6. Cellular cycle 1.6.1. Mitosis 1.6.1.1. Cytokinesis 1.6.2. Meiosis 1.6.2.1. Meiosis I. First meiotic division 1.6.2.2. Meiosis II. Second meiotic division 1.6.2.3. Result of meiosis 1.6.3. Differences between mitosis and meiosis 1.6.4. Biological importance of mitosis and meiosis 1.7. Bibliography 2. Genetic information 2.1. Nucleic acids 2.1.1. DNA 2.1.2. RNA 2.1.3. Control of protein synthesis 2.2. DNA and molecular genetics 2.3. Gene concept 2.4. Replication of DNA 2.5. DNA to RNA transcription 2.6. Genetic code 2.7. Translation of RNA to proteins 2.8. Mutations Relations with evolution 2.9. Biotechnology 2.10. Genetic engineering: techniques and applications 2.10.1. Cloning 2.10.2. Human Genome Project 2.11. Bioethics 2.12. Bibliography 3. Biological inheritance 3.1. The inheritance and transmission of characters 3.2. Introduction and development of Mendel's Laws 3.2.1. Mendel's First Law 3.2.2. Mendel's second law 3.2.3. Mendel's third law 3.3. Chromosomal basis of Mendel's Laws 3.3.1. Exceptions to Mendel's Laws 3.3.2. Chromosomal theory of heredity 3.3.3. Genetics concepts 3.3.4. Types of inheritance 3.4. Human genetics 3.4.1. Inheritance of blood groups 3.4.2. Sex inheritance 3.4.3. Sex-linked inheritance 3.4.4. Heredity influenced by sex 3.5. Genetics problems 3.5.1. Inheritance of a character (problems solved) 3.5.1.1. Albinism (problems solved) 3.5.1.2. Rh groups (problems solved) 3.5.1.3. Eye color (problems solved) 3.5.1.4. More inheritance problems of a character 3.5.1.5. More inheritance problems of a character 3.5.1.6. More inheritance problems of a character 3.5.1.7. More inheritance problems of a character 3.5.2. Two-character inheritance (problems solved) 3.5.2.1. More two-character genetic inheritance solved problems 2 3.5.2.2. More two-character genetic inheritance solved problems 3 3.5.2.3. More two-character genetic inheritance solved problems 4 3.5.2.4. More two-character genetic inheritance solved problems 5 3.5.3. Codominance and intermediate inheritance (problems solved) 3.5.3.1. More codominance and intermediate inheritance problems 2 3.5.4. Sex-linked inheritance (problems solved) 3.5.4.1. Color blindness or daltonism (problems solved) 3.5.4.1.1. More color blindness problems or daltonism 3.5.4.2. Hemophilia (problems solved) 3.5.4.3. Sex-linked inheritance (two characters) 3.5.4.4. More sex-linked inheritance problems 3.5.5. Sex-influenced inheritance (problems solved) 3.5.6. Multiple alleles (problems solved) 3.5.6.1 AB0 blood groups (problems solved) 3.5.6.1.1. More AB0 blood group problems solved 2 3.5.6.1.2. More AB0 blood group problems solved 3 3.5.7. Genealogical trees 3.5.7.1. Family Trees 2 3.5.7.2. Family Trees 3 3.6. Bibliography 4. Origin and evolution of living beings 4.1. Hypothesis about the origin of life on Earth 4.2. Evolution of living beings 4.3. Theories of evolution 4.3.1. Lamarck 4.3.2. Darwin and Wallace 4.3.3. Neo-Darwinism 4.3.4. Other evolutionary theories 4.4. Evidences of evolution 4.4.1. Anatomical evidence of evolution 4.4.2. Embryological evidence of evolution 4.4.3. Paleontological evidence of evolution 4.4.4. Biogeographic evidence of evolution 4.4.5. Biochemical evidence of evolution 4.5. Mechanisms of evolution 4.5.1. Genetic variability 4.5.2. Natural selection 4.5.3. Consequences of evolution 4.5.3.1. Adaptation of organisms 4.5.3.2. Speciation 4.5.3.3. Species diversification 4.6. Human evolution: process of hominization 4.6.1. Primates 4.6.2. Hominids 4.6.3. The human being 4.7. Bibliography 5. The history of the Earth 5.1. The origin of the Earth 5.2. Earth, a changing planet 5.3. Geological time: historical ideas about the age of the Earth 5.4. Dating methods 5.4.1. Relative dating 5.4.1.1. Geological history exercises - relative dating 5.4.2. Absolute dating 5.5. Fossils 5.5.1. Fossils in Aragon 5.6. Geological history of the Earth 5.6.1. Precambrian 5.6.2. Phanerozoic 5.6.2.1. Paleozoic 5.6.2.2. Mesozoic 5.6.2.3. Cenozoic 5.7. Bibliography 6. Structure and dynamics of the Earth 6.1. Earth study methods 6.1.1. Seismic discontinuities 6.2. Structure and composition of the Earth 6.2.1. Geochemical model 6.2.2. Dynamic model 6.3. Bibliography 7. Plate tectonics 7.1. From continental drift to plate tectonics 7.1.1. Wegener continental drift 7.2. Plate Tectonics and its manifestations 7.2.1. Lithospheric plates 7.2.2. Oceanic ridges 7.2.2.1. Expansion of the ocean floor 7.2.3. Ocean trenches 7.2.4. Transforming faults 7.2.5. Formation of mountain ranges 7.3. The Wilson cycle 7.4. Rock deformation 7.4.1. Folds 7.4.2. Faults 7.4.3. Joints 7.4.4. Mixed structures 7.5. Bibliography 8. Ecosystems 8.1. Ecosystem structure 8.1.1. Types of ecosystems 8.1.1.1. Aquatic ecosystems 8.1.1.2. Terrestrial ecosystems 8.1.1.2.1. Urban ecosystems 8.2. Components of the ecosystem: community and biotope 8.2.1. Biotope 8.2.2. Biocenosis or community 8.3. Habitat and ecological niche 8.4. Limiting factors and adaptations 8.5. Tolerance limit 8.6. Trophic levels 8.7. Trophic relationships: chains and networks 8.8. Ecological pyramids 8.9. Self-regulation of the ecosystem, the population and the community 8.9.1. Intra and interspecific relationships 8.10. Matter cycle and energy flow 8.11. Biogeochemical cycles 8.11.1. Carbon cycle 8.11.2. Nitrogen cycle 8.11.3. Phosphorus cycle 8.12. Ecological successions 8.13. Bibliography 9. Resources and environmental impacts 9.1. Human activity and the environment 9.2. Natural resources and their types 9.3. Environmental impacts 9.3.1. Pollution of the atmosphere 9.3.1.1. Air pollutants 9.3.1.2. Acid rain 9.3.1.3. The smog 9.3.1.4. Ozone layer hole 9.3.1.5. Increased greenhouse effect 9.3.1.6. Climate change 9.3.2. Noise pollution 9.3.3. Light pollution 9.3.4. Water contamination 9.3.4.1. Water pollutants 9.3.4.2. Water eutrophication 9.3.4.3. Aquifer reduction 9.4. Soil 9.4.1. Soil contamination 9.5. Main environmental problems of Aragon 9.6. Overpopulation and its consequences 9.7. Waste and its management 9.8. Bibliography and student work « Previous \| Next » 3.5.1.3. Eye color (problems solved) Autosomal dominant inheritance. Eye color (Page 4) The color of the eyes is somewhat more complicated than what we are going to see here. It is not only determined by a single gene, but two are involved. The chromosome 15 with alleles M and m, where the presence, at the least, a M determines that the eyes are brown and the presence of the two eyes mm determines that are clear, blue or green. We, in the simulation, will stay here. As we say, this type of inheritance is complicated because the other gene, on chromosome 19, will determine in people with light eyes (mm) whether the eyes will be blue or green . Individuals who already have M in the first gene will have brown eyes regardless of the combination in the second gene. Therefore, this second gene only influences the phenotype in individuals of genotype mm. It has two alleles, V and v, the green eye color being dominant. Thus, if we have at least one V ( VV or Vv ) in this gene, the eye color will be green, and if we have both vv alleles, the eye color will be blue.. As we have said, in the simulation we will see what the eyes of the descendants (brown or light) look like depending on the genotype of the parents. Genetics problem 19 In humans, the brown color of the eyes (A) is dominant over the blue color (a). A brown-eyed man and a blue-eyed woman have two children, one with brown eyes and the other with blue eyes. Find out all the genotypes: Feedback Brown eye color (A) is dominant over blue (a) Parents: A- x aa Children: A- aa Since the couple have a blue-eyed child, the father must have passed on a gene a. Therefore, the father will be Aa. Similarly, the brown-eyed son, having a blue-eyed mother, will have to be Aa. Parents: Aa x aa Children: Aa aa You can also see the explanation in this animation. Genetics problem 20 The blue color of the eyes in men is due to a recessive gene with respect to its allele for the color brown. The parents of a blue-eyed male both have brown eyes. What are their genotypes? Feedback If the man is homozygous recessive (aa) because he has blue eyes, and his parents have brown eyes, in order to pass on the gene a, they will have to be Aa. Parents: Aa x Aa Son: aa Genetics problem 21 a) Olga and Juan, both with brown eyes, have a male child (Luis) with blue eyes. What type of inheritance occurs? Indicate the genotype of the three individuals. b) Luis, the son of Olga and Juan, married María, with brown eyes, whose mother (Pilar) was blue-eyed and whose father was brown-eyed. Maria had a brother with blue eyes. Luis and María had a son (Álvaro), with brown eyes. Indicate the genotypes of all the characters in this question. Feedback a) If both parents have brown eyes and have a child with blue eyes, blue cannot be dominant over brown. M > m Brown: MM and Mm. Blue: mm Parents: (Olga) Mm x (Juan) Mm Son: (Luis) mm Like Luis, the son, has blue eyes (mm), his brown-eyed parents have to be heterozygous (Mm). The inheritance is of the dominance-recessiveness type. b) Luis married María, with brown eyes (M-), whose mother (Pilar) was blue-eyed (mm) and whose father was brown-eyed (M-). Maria had a brother with blue eyes (mm). As Pilar (mm) had blue eyes, María, with brown eyes, will be Mm. Since Maria had a brother with blue eyes (mm), her father has to be brown-eyed (Mm). Luis (mm) and María (Mm) had a son (Álvaro), with brown eyes (Mm). Genetics problem 22 In the human species the color of the eyes is determined by a pair of alleles. A blue-eyed man marries a brown-eyed woman. The woman's mother was blue-eyed and the father, who had a blue-eyed brother, was brown-eyed. From the marriage a son with brown eyes was born. Indicates the probability of having a child with blue eyes. The color of brown eyes dominates over that of blue eyes. Feedback Man (aa) Woman (A-) but since her mother had blue eyes, the woman is Aa. His father was A_, because he had brown eyes. They tell us that he had a brother with blue eyes (aa), but that only tells us that, at least, his parents had each one, nothing more. It would be irrelevant, since we had already determined that the woman was Aa. Crossing: aa x Aa F1: Aa aa 50% of the children will have blue eyes (aa). Genetics problem 23 In the human species, the color of the eyes is an autosomal character where the allele of the brown color "A" dominates over that of the blue color "a". A brown-eyed man, whose mother has blue eyes, has two descendants with a blue-eyed woman. What are the genotypes of men and women? And those of the descendants? What is the probability that this couple has descendants with blue eyes? And the probability of having descendants with brown eyes? Reason for the answers. Feedback The brown-eyed man of a blue-eyed mother (aa) will be heterozygous (Aa). His father would have brown eyes (A-). The woman is homozygous recessive (aa), since she has blue eyes. aa x A_ Aa x aa Aa aa The descendants of this pair will be 50% Aa (brown eyes) and 50% aa (blue eyes). Genetics problem 24 In the human species, black eyes dominate over blue eyes. A black-eyed man is joined by a blue-eyed woman and they have a blue-eyed son. What are the genotypes of the black-eyed man, the blue-eyed woman, and the blue-eyed son? Give reasons for the answer. Can this couple have a child with black eyes? Give reasons for the answer. Feedback Black eyes Blue eyes P: A_ x aa Gametes A _ a F1 Aa a_ The man, to have blue children aa, has to be Aa. 50% of the children will have black eyes Aa. Genetics problem 25 We assume that eye color in humans is controlled by a gene with two alleles: -b- responsible for blue eyes and -B, which produces brown eyes and is dominant over -b-: a) What is the genotype of a brown-eyed man who has a blue-eyed son with a blue-eyed woman? Reason for the answer; b) Considering the same previous mating, what proportion of the two eye colors would be expected in the offspring?; c) What proportion would be expected in terms of eye color in the progeny of a mating between two brown-eyed individuals, each of which had a parent with blue eyes? Represents mating; d) Which of Mendel's laws is supposed to apply in the proposed crossing in the question? Reason for the answer. Feedback It is a problem in which only one character determined by two alleles appears, where B (brown eyes) dominates over b (blue eyes). a) What is the genotype of a brown-eyed man who has a blue-eyed son with a blue-eyed woman Parents B_ x bb Gametes B _ b Blue-eyed son bb. For the son to have blue eyes bb, the father has to be Bb. b) What proportion of the two eye colors would be expected in the descendants?; Parents Bb x bb Gametes B b b Sons Bb bb 50% brown 50% blue c) What proportion would be expected in terms of eye color in the progeny of a mating between two brown-eyed individuals, each of which had a parent with blue eyes? If the brown-eyed (B_) individuals have a blue-eyed (bb) parent, the individuals must be Bb. Parents Bb x Bb Gametes B b B b Sons BB Bb Bb bb 75% brown eyes 25% blue eyes d) In this crossing, Mendel's 2nd law or segregation of the genes of each allele has been applied, the two alleles of the heterozygous separate when the gametes are formed. Licensed under the Creative Commons Attribution Share Alike License 4.0 « Previous \| Next » You can ask, comment, contribute, get in touch with other users in the forum of this course. This course is translated from https://biologia-geologia.com/BG4/
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Autosomal dominant inheritance. Eye color (Page 4)

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