3.5.3. Codominance and intermediate inheritance (problems solved)

Codominance and intermediate inheritance (problems solved). (Page 14)

You will remember from when we saw the types of genetic inheritance, that intermediate dominance occurs when the phenotype of the heterozygous, descended from two different codominant homozygous parents, presented an intermediate phenotype between that of the two parents.

In codominance, on the other hand, the heterozygous offspring manifests a phenotype in which the characteristics of both parents are manifested.

In addition to the problems you have below, you have more problems of this type on the next page:

More codominance and intermediate inheritance problems (15).

Nomenclature for genetic problems

Since uppercase letters represent dominance and lowercase letters, recessivity, in the case of codominance problems, we will represent the different alleles by means of subscripts or superscripts of the same representative letter of the gene. We will capitalize this letter, since both alleles are expressed to a greater or lesser degree. For example, A₁ A₂.

In the case of blood groups the MN system, the gene is represented by the letter L and the two alleles are L^M and L^N. Possible genotypes are L^ML^M, L^NL^N and L^ML^N.

Genetics problem 103

In one species of plants the flowers can be red, white or pink. It is known that this trait is determined by two allele genes, red (C^r) and white (C^b) , with intermediate inheritance.

How could they be the descendants of the cross between plants with pink flowers?

Genetics problem 104

In one species of plants the flowers can be red, white or pink. It is known that this trait is determined by two allele genes, red (C^r) and white (C^b), with intermediate inheritance.

How could they be the descendants of the cross between plants with pink flowers and plants with red flowers?

Genetics problem 105

In one species of plants the flowers can be red, white or pink. It is known that this trait is determined by two allele genes, red (C^r) and white (C^b) , with intermediate inheritance .

How could they be the descendants of the cross between plants with pink flowers and plants with white red flowers?

Nomenclature for genetic problems

In cases of intermediate inheritance, a new phenotype appears, although it does not necessarily have to be intermediate. They are different alleles of the same gene, so we will use a single letter for all of them.

We can use an uppercase letter (A) and a lowercase letter (a), since in this case there is neither dominance nor recessivity, or use a capital letter for the two alleles, with a subscript or superscript to differentiate them (C¹, C²).

Genetics problem 106

In a certain breed of hen, the C^N allele indicates black, the C^B , white, both codominant, and when both alleles appear in an individual, C^NC^B , the hen's plumage is blue.

a) How are the descendants of the crossing of a blue hen and a black hen?

b) How are the descendants of the cross between two blue chickens?

c) How are the descendants of the crossing of a blue hen and a white hen?

Genetics problem 107

Reason the answers: The PP genotype determines the presence of ruffled feathers in hens, while pp produces smooth feathers and Pp, gives rise to an intermediate phenotype. Of the crossing of a hen with curly feathers and a rooster with smooth feathers,

a) what proportion of their offspring is expected from intermediate feathers?

b) and what proportion of intermediate feathers will be obtained from crossing a rooster and hen with intermediate feathers?

c) why can't Mendel's laws apply to prokaryotic organisms?

Genetics problem 108

By crossing a gray-winged butterfly with another with black wings, an offspring made up of 93 black-winged butterflies and 93 gray-winged butterflies was obtained. The gray-winged butterfly was crossed with another with white wings, obtaining an offspring made up of 35 white butterflies and 35 gray butterflies. Find out the genotypes, both of the butterflies that are crossed and of the offspring. Reason for the answer.

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a) The gray butterfly (C^BC^N) was crossed with the black one (C^NC^N) and 93 gray and 93 black were obtained.

Crossing: C^NC^N x C^BC^N

Gametes: C^N C^B C^N

F1: C^BC^N C^NC^N 93 gray and 93 black, 1: 1 ratio

b) The gray-winged butterfly (C^BC^N) was crossed with another with white wings C^BC^B, obtaining an offspring made up of 35 white butterflies (C^BC^B ) and 35 gray butterflies (C^BC^N) .

Crossing: C^BC^B x C^BC^N

Gametes: C^B C^B C^N

F1: C^BC^N C^BC^B 35 gray and 35 white, 1:1 ratio

Genetics problem 109

Two "morning glory" plants are homozygous for flower color. One of them produces ivory flowers and the other red flowers. Tell how the genotypes and phenotypes originating from the crossing of both plants will be, knowing that "B" is the gene responsible for the ivory color and "R" is the one that conditions the red color, both genes being equipotent.

Genetics problem 110

A gardener who had rose-flowered morning glory plants crossed two of his plants with the idea of obtaining plants of the same color. His surprise was that red, pink and white flowers appeared in the offspring in the ratio 1: 2: 1.

Indicates the genotype of the plants of the described cross.

Genetics problem 111

In guinea pigs there are three varieties for the coat: yellow, cream and white. Crossing two cream-colored guinea pigs produces descendants of all three varieties. Deduce what type of inheritance the character presents by raising the cross.

Genetics problem 112

There are varieties of a plant with white flowers and varieties with purple flowers. The F1 of a cross between plants of the two varieties was light purple, and the F2 gave 1/4 violet, 2/4 light violet and 1/4 white. Explain the type of inheritance and perform the crossing.

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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 » 3.5.3. Codominance and intermediate inheritance (problems solved) Codominance and intermediate inheritance (problems solved). (Page 14) You will remember from when we saw the types of genetic inheritance, that intermediate dominance occurs when the phenotype of the heterozygous, descended from two different codominant homozygous parents, presented an intermediate phenotype between that of the two parents. In codominance, on the other hand, the heterozygous offspring manifests a phenotype in which the characteristics of both parents are manifested. In addition to the problems you have below, you have more problems of this type on the next page: More codominance and intermediate inheritance problems (15). Nomenclature for genetic problems Since uppercase letters represent dominance and lowercase letters, recessivity, in the case of codominance problems, we will represent the different alleles by means of subscripts or superscripts of the same representative letter of the gene. We will capitalize this letter, since both alleles are expressed to a greater or lesser degree. For example, A₁ A₂. In the case of blood groups the MN system, the gene is represented by the letter L and the two alleles are L^M and L^N. Possible genotypes are L^ML^M, L^NL^N and L^ML^N. Genetics problem 103 In one species of plants the flowers can be red, white or pink. It is known that this trait is determined by two allele genes, red (C^r) and white (C^b) , with intermediate inheritance. How could they be the descendants of the cross between plants with pink flowers? Feedback Crossing: C^rC^b (pink) x C^rC^b (pink) Gametes: C^rC^b C^rC^b F1: C^rC^r C^rC^b C^rC^b C^bC^b 25% red 50% pink 25% white Genetics problem 104 In one species of plants the flowers can be red, white or pink. It is known that this trait is determined by two allele genes, red (C^r) and white (C^b), with intermediate inheritance. How could they be the descendants of the cross between plants with pink flowers and plants with red flowers? Feedback Crossing: C ^rC^b (pink) x C^rC^r (red) Gametes: C ^rC ^b C ^r F1: C^rC^r C ^r C ^b 50% red 50% pink Genetics problem 105 In one species of plants the flowers can be red, white or pink. It is known that this trait is determined by two allele genes, red (C^r) and white (C^b) , with intermediate inheritance . How could they be the descendants of the cross between plants with pink flowers and plants with white red flowers? Feedback Crossing: C ^rC ^b (pink) x C ^b C^b (white) Gametes: C^rC^b C^b F1: C^rC^b C^bC^b 50% pink 50% white Nomenclature for genetic problems In cases of intermediate inheritance, a new phenotype appears, although it does not necessarily have to be intermediate. They are different alleles of the same gene, so we will use a single letter for all of them. We can use an uppercase letter (A) and a lowercase letter (a), since in this case there is neither dominance nor recessivity, or use a capital letter for the two alleles, with a subscript or superscript to differentiate them (C¹, C²). Genetics problem 106 In a certain breed of hen, the C^N allele indicates black, the C^B , white, both codominant, and when both alleles appear in an individual, C^NC^B , the hen's plumage is blue. a) How are the descendants of the crossing of a blue hen and a black hen? b) How are the descendants of the cross between two blue chickens? c) How are the descendants of the crossing of a blue hen and a white hen? Feedback Black hen: C^NC^N White hen: C^BC^B Blue hen: C^NC^B a) Crossing: Blue hen: C^NC^B x Black hen: C^NC^N Gametes: C ^N C ^B C ^N F1: C^NC^B (50% blue) C^NC^N (50% black) b) Crossing: Blue hen: C^NC^B x Blue hen: C^NC^B Gametes: C ^N C ^B C ^N C ^B F1: C^BC^B (25% white) C^NC^B (50% blue) C^NC^N (25% black) c) Cross: Blue hen: C^NC^B x White hen: C^BC^B Gametes: C^N C^B C^B F1: C^NC^B (50% blue) C^BC^B (50% white) Genetics problem 107 Reason the answers: The PP genotype determines the presence of ruffled feathers in hens, while pp produces smooth feathers and Pp, gives rise to an intermediate phenotype. Of the crossing of a hen with curly feathers and a rooster with smooth feathers, a) what proportion of their offspring is expected from intermediate feathers? b) and what proportion of intermediate feathers will be obtained from crossing a rooster and hen with intermediate feathers? c) why can't Mendel's laws apply to prokaryotic organisms? Feedback Cross: hen with curly feathers (PP) and a rooster with smooth feathers (pp), a) PP x pp Gametes P p F1: Pp (100% intermediate feathers) b) Cross 2: Pp x Pp Gametes: P p P p F2: PP 2Pp pp. 1/2 = 50% will have intermediate feathers c) Prokaryotic organisms reproduce asexually, they are haploid , there is a single copy of the bacterial chromosome, that is, a single gene for a character. Genetics problem 108 By crossing a gray-winged butterfly with another with black wings, an offspring made up of 93 black-winged butterflies and 93 gray-winged butterflies was obtained. The gray-winged butterfly was crossed with another with white wings, obtaining an offspring made up of 35 white butterflies and 35 gray butterflies. Find out the genotypes, both of the butterflies that are crossed and of the offspring. Reason for the answer. Feedback a) The gray butterfly (C^BC^N) was crossed with the black one (C^NC^N) and 93 gray and 93 black were obtained. Crossing: C^NC^N x C^BC^N Gametes: C^N C^B C^N F1: C^BC^N C^NC^N 93 gray and 93 black, 1: 1 ratio b) The gray-winged butterfly (C^BC^N) was crossed with another with white wings C^BC^B, obtaining an offspring made up of 35 white butterflies (C^BC^B ) and 35 gray butterflies (C^BC^N) . Crossing: C^BC^B x C^BC^N Gametes: C^B C^B C^N F1: C^BC^N C^BC^B 35 gray and 35 white, 1:1 ratio Genetics problem 109 Two "morning glory" plants are homozygous for flower color. One of them produces ivory flowers and the other red flowers. Tell how the genotypes and phenotypes originating from the crossing of both plants will be, knowing that "B" is the gene responsible for the ivory color and "R" is the one that conditions the red color, both genes being equipotent. Feedback B = Ivory. R = Red. B = R Crossover: BB x RR Gametes: B R F1: BR 100% Roses (intermediate phenotype) Genetics problem 110 A gardener who had rose-flowered morning glory plants crossed two of his plants with the idea of obtaining plants of the same color. His surprise was that red, pink and white flowers appeared in the offspring in the ratio 1: 2: 1. Indicates the genotype of the plants of the described cross. Feedback Cross: Pink flower BR x Pink flower BR Gametes: B R B R F1: BB BR BR RR Phenotypes: White flowers Pink flowers Red flowers It is a case of intermediate inheritance. Genetics problem 111 In guinea pigs there are three varieties for the coat: yellow, cream and white. Crossing two cream-colored guinea pigs produces descendants of all three varieties. Deduce what type of inheritance the character presents by raising the cross. Feedback Seeing that there are three varieties for the coat, we can begin to think that it is a type of intermediate dominance. And if they tell us that by crossing two cream-colored guinea pigs, descendants of the three varieties are obtained, it is confirmed. Possible genotypes: Yellow AA White BB Cream AB Cross: AB (cream) x AB (cream) Gametes: A B x A B F1: AA (yellow) AB (cream) AB (cream) BB (white) Genetics problem 112 There are varieties of a plant with white flowers and varieties with purple flowers. The F1 of a cross between plants of the two varieties was light purple, and the F2 gave 1/4 violet, 2/4 light violet and 1/4 white. Explain the type of inheritance and perform the crossing. Feedback It is a case of intermediate inheritance. Since the F1 individuals are all the same (heterozygous), the parents will be homozygous. Parents: BB VV F1: BV Second crossing: BV x BV Gametes: B V B V F2: BB BV BV VV Phenotype: 25% White 50% Light Violet 25% Violet 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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Codominance and intermediate inheritance (problems solved). (Page 14)

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