1. What is the difference between heterozygous and homozygous individuals?
2.Two mice are heterozygous for albinism. The dominant allele codes for normal pigmentation,and the recessive allele codes for no pigmentation. What percentage of their offspringwould have an albino phenotype? Write down a cross and explain.
3.According to Mendel experiment when a tall, purple-flowered pea plant can self-pollinate whatis the genotype of the plant whose phenotype appeared once out of every 16 offspring. Writedown a cross and explain.
4. Black eyes are dominant to orange eyes, and green skin is dominant to white skin. Tom withblack eyes and green skin, has a parent with orange eyes and white skin. Ann has orange eyesand white skin. If Tom and Ann were to mate, the predicted phenotypic ratio of their offspringwould be _____. Write down a cross and explain how you call such cross.
5. In the following cross (picture) the genotype of the female parent is AaBb. What is thegenotype of the male parent? Black eyes are dominant to orange eyes, and green skin isdominant to white skin. Write down a cross and explain. (See attached photos)
6.How many unique gametes could be produced through independent assortment by anindividual with the genotype AaBbCCDdEE? Write all of them.
7. Write downstatement which correctly describes how Mendel accounted for the observationthat traits had disappeared in the F1 generation and then reappeared in the F2 generation?
8.The Mendel law of segregation states that......
9. Mendel studied pea plants dihybrid for seed shape (round versus wrinkled) and seed colour(yellow versus green). The table below shows the F1 generation that result fromself-pollinationfour different parent pea plants. Use the phenotypes of the F1 progeny to deduce the genotypeand phenotype of each parent plant (see attached photo 2).
10. A man has extra digits (six fingers on each hand and six toes on each foot - it is a dominanttrait). His wife and their daughter have the normal number of digits. The couple's second childhas extra digits. What is the probability that their next (third) child will have extra digits?Explain why.
11.A cross between a red-flowered radish plant and a blue-flowered plant yields all purpleoffspring. The part of the radish we eat may be oval or long (the dominant trait). If true-breeding red long radishes are crossed with true-breeding blue oval radishes, the F1 will beexpected to exhibit which genotypes and phenotypes? Cross two plants from F1 and write F2generation. Explain what does this say about the parental traits?
12.Skin colour in a certain species of fish is inherited via a single gene with four different alleles.One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4 (S2S4). If eachallele confers a unit of colour darkness such that S1 has one unit, S2 has two units, and so on,then what proportion of their offspring would be expected to have five units of colour? Writedown a cross and explain.
13.Cacti with the dominant allele have sharp spines, whereas homozygous recessive cacti havedull spines. At the same time, a second gene determines whether cactuses have spines, becausehomozygous recessive cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce only sharp-spined cactuses. Cross themand write down also F2 generation. Explain the pattern of inheritance.
14. Feather colour in budgies is determined by two different genes. A breeder crossed true-breeding blue budgie with a true-breeding yellow budgie and in F1 only green offspring wereobserved. When these F1 offspring are mated they produce green, blue, yellow and whitebudgies. Write down this cross and explain the inheritance pattern for this trait.
15. In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. Awoman who has blood type A positive has a daughter who is type O positive and a son who istype B negative. Write down all genotypes and phenotypes possible for the father andgenotypes of the rest of family. Explainyour answer.
16.Marfan syndrome in humans is caused by an abnormality of the connective tissue proteinfibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine,sometimes weakened arterial walls, and sometimes eye problems, such as lens dislocation.Explain what kind of inheritance pattern would you conclude about Marfan syndrome fromthis information? Use genetic terms and write down name and description of thisphenomenon.
17. The law of independent assortment states that.......
18. When a chicken with the creeper phenotype (the legs are short and stunted) crossed with normal chicken, 5 offspring were creeper and 4 were normal. If two creeper chickens from F1 generation were crossed they produced 12 creeper and 6 normal chickens. Write down the cross and explain the mode of inheritance.
19. The typical tail length of adult giant armadillo species varies in a population along a continuum.When it was crossed an armadillo with 50 cm tail to an armadillo with 40 cm tail in the F1generation 45 cm-tailed offspring were observed. If members of the F1 are mated offspring'stails could be classified into 5 different lengths. Write down the cross and explain the mode of inheritance.How many gene pairs are involved?
20.When a homozygous black feathered chicken was mated with a homozygous white featheredchicken their offspring have speckled phenotype. If members of F1 generation are mated, thefeathers of F2 generation chickens are black, white and speckled.Write down the cross andexplain the mode of inheritance.