Concept explainers
a.
To determine: The possible
Introduction: The genotype is the genetic constitution of the organism whereas the phenotype refers to external characters visible in an organism. The alleles are the contrasting forms of a gene, and one of them is dominant, and the other is recessive.
b.
To determine: The possible genotypes for the co-dominant alleles a, b, c, and recessive allele d.
Introduction: The dominant allele masks the expression of the recessive allele. Therefore, the dominant allele is expressed in homozygous and heterozygous genotypes whereas the recessive phenotype is only expressed under homozygous condition.
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Human Heredity: Principles and Issues (MindTap Course List)
- Part 1 With use of Punnett diagrams discuss how the results of experiments carried out by Austrian monk Gregor Mendel on pea plants brought about the Law of Dominance, the Law of Segregation, and the Law of Independent assortment. Part 2 In humans, the gene that produces the disease Sickle Cell Anaemia is recessive to the gene for healthy haemoglobin production. a) How can two phenotypically healthy parents have a child who suffers from Sickle cell Anaemia? In your answer use suitable letters to show the genotypes of the parents and construct a Punnett diagram to show all the possibilities of the children's genotypes. b) Based on the outcome of your Punnett diagram, state and explain the probability of a child being a sufferer of Sickle Cell Anaemia and the probability of a child not suffering from the disease. c) If an individual who suffers from Sickle cell disease has a child with someone who is healthy (and not carrying the sickle cell gene), what is the probability that the child…arrow_forwardThe B allele confers black coat color and the b allele brown coat color in Labrador dogs. When another gene, E, is inherited, the coat is golden no matter what the B phenotype is. A dog of genotype ee expresses the black phenotype. What unusual phenomenon is at work in this disorder?arrow_forwardMendel's Laws of Inheritance Menders Success Menders approach to the study of heredity was effective for several reasons. Foremost was his choice of experimental subject, the pea plant Pisum sativum. Monohybrid Crosses Mendel began by studying monohybrid crosses— those between parents that differed in a single characteristic. The principle of segregation (Mendel's first law) states that each individual diploid organism possesses two alleles for any particular characteristic. These two alleles segregate (separate) when gametes are formed, and one allele goes into each gamete. Furthermore, the two alleles segregate into gametes in equal proportions.The concept of dominance that, when two different alleles are present in a genotype, only the trait of the dominant allele is observed in the phenotype. Multiple-Loci Crosses Dihybrid Crosses In addition to his work on monohybrid crosses, Mendel also crossed varieties of peas that differed in two characteristics (dihybrid crosses).…arrow_forward
- In bears fur colour can be either yellow or tan, and is determined by two alleles of the C gene. A heterozygous bear is observed to present a fur pattern of yellow and tan patches. Explain why this can occur.arrow_forwardHomozygous dominant parent (PP), and a Homozygous recessive or just simply say recessive parent (pp): a. Fill in the Punnett square. Each box represents a genotype possibility for an offspring. b. Place the allele donated by each parent in the corresponding box. Now list the possible genotypes and their corresponding phenotype. c. If an individual's genotype is heterozygous, the dominant trait will be expressed in the phenotype. Give the percent possible for the phenotypes. P P p p Genotype: ______________ Phenotype: ______________ Phenotype % probable: __________ 2. Cross between a Homozygous dominant parent (PP) and a Heterozygous parent (Pp). Fill in as in step one. 3. Cross between a Heterozygous parent (Pp), and another Heterozygous parent (Pp). Fill-in as before. 4. Test cross: A test cross is between a recessive parent (pp), and a Heterozygous parent…arrow_forwardRetinitis pigmentosa, a form of blindness in man, maybe caused either by a dominant autosomal gene R, or a recessive autosomal gene a. An afflicted man whose parents are both normal marries a woman with genotype AaRr. a. What proportion of the children are expected to suffer from this affliction if R and A are inherited independently? b. If this couple want to have normal children only, what isthe probability of having normal children?arrow_forward
- Mendelian Genetics [6F.R]:Question 1 In rabbits, grey fur (G) is dominant to white fur (g) and black eyes (B) are dominant to red eyes (b). A male rabbit with the genotype GgBb is crossed with a female rabbit with the genotype ggbb. What percent of the offspring will have white fur and red eyes? Select one: 25% 50% 100% 0% 1000arrow_forwardchoose only if its a or b no need to explain. 1.) In sex-linked inheritance, if a colour blind man mates with a heterozygous woman, what is the expected ratio of phenotypes among the offsprings? Question 6 options: a.) normal female : heterozygous female : normal male : colour-blind male (1 : 1 : 1 : 1) b.) normal female : normal male : colour-blind male (2 : 1 : 1) c.) normal female : heterozygous female : normal male ( 1 : 1 : 2) d.) heterozygous female: colour blind female: normal male: colour-blind male (1: 1: 1: 1) 2.) The human female has two X chromosomes. In which of the following ways will x-linked traits be inherited among humans? a.) from mother to daughter only b.) from mother to son only c.) from mother to both son and daughter d.) from mother neither to son, nor to daughterarrow_forwardDiscuss how Mendel’s monohybrid results served as the basis for all but one of his postulates. Which postulate was not based on these results? Why?arrow_forward
- Mendelian Genetics Hermione's parents are muggles (cannot perform magic). How is it possible for Hermione to do magic? What are the genotypes of her parents? Is the ability to perform magic dominant or recessive? Hagrid is a half-giant. If his father was a giant, what is the phenotype of his mother? Which trait is dominant?arrow_forwardTay–Sachs disease is caused by recessive alleles on anautosome. In which case(s) could two parents with anormal phenotype have a child with Tay–Sachs?a. Both parents are homozygous for a Tay–Sachs allele.b. Both parents are heterozygous for a Tay–Sachsallele.c. One parent is homozygous for a Tay–Sachs allele,and the other is heterozygous.arrow_forwardIn the common daisy, genes A and B control flower color. Both genes have a dominant allele (A or B) and a recessive allele (a or b). At least one copy of each dominant allele is required for flowers to be colorful instead of white. (Explain and Justify your answers) 21.1) Predict the genotypes and phenotypes of the F1 progeny of a cross between two white-flowered plants, one homozygous AA and the other homozygous BB. A) AA bb, white B) aa BB, white C) Aa Bb, colorful D) Aa Bb, white E) aa bb, colorful 21.2) Predict the phenotypic ratio of the F2 progeny of a cross between two white-flowered plants, one homozygous AA and the other homozygous BB. A) 3 colorful : 1 white B) 9 colorful : 7 white C) 9 white : 7 colorful D) 15 white : 1 colorful E) 15 colorful : 1 white 21.3) The inheritance pattern of daisy flower color provides an example of what type of gene interaction? A) additivity…arrow_forward
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