Alternate Genetics Problems

These problems are made up, the actual traits listed may not be representative of what truly happens in nature, this is an exercise in genetic problems, not a guide to the heredity of organisms.

Matt’s hints to solving these problems

-stay organized

-use uppercase and lower case letters carefully, if you need to, use cursive to differentiate them

-write down exactly what you know

-make sure that you are answering the question, not blindly crossing the masses

-know that there will be enough given info to solve the problems, extracting this info is half the battle

-practice, when you do enough of these you start to appreciate patterns

-if it doesn’t say to link the trait by sex, don’t do it, it is a trick! All of this is male – female.

-remember the point of the square, it is to give us an EXPECTED ratio! Not an absolute truth, it is EXPECTED that 50% of all children will be boys and 50% will be girls, we know this isn’t always what happens in real life.

Like Problem 1. In the Hawaiian flower, the beach Naupaka, Yellow Flowers are recessive to the dominant trait of white flowers. Give the phenotypic and genotypic ratios of the following crosses.

a) homozygous white flower X yellow flower

b) heterozygous flower X yellow flower

c) heterozygous flower X heterozygous flower

Like problem 2. In Nene birds, the state bird of Hawaii, the fast (F) condition is dominant to to the slow (f) condition. A very fast male Nene is bread with three other female nene birds. With bird A, which is slow, a fast bird is produced. With bird B, also a slow poke, a slow bird is produced. With the third bird, C, which is fast, the offspring is fast. What is the genotype of the three female birds and the male?

Like problem 3. The ability to surf the North Shore of Hawaii is a recessive condition, expressed phenotypically by very few. A surfer, who has been riding the waves in this break his whole life, marries a woman who cannot surf at all. The girl’s father, however, was one of the all time greatest surfers on the North Shore. Concerned that his children will be unable to tackle these waves, the father wants to know what kind of children he can expect to have.

Like problem 4. At the research labs on Coconut Island the University of Hawaii graduate students are trying to manipulate a group of talapia fish. The darker the fish, the more reproductive success it seems to have. Their need for a specific cross will greatly assist them in their aquaculture studies. One of the students has learned that the trait for pure white scales (B) is codominant with pure black scales (B’) with the heterozygous condition producing a rather odd looking spotted fish. The student has a tank with an odd spotted male and an entire school of white fish. How can the student successfully produce a school of black fish? Explain.

Like problem 5. Pineapple has a very sweet taste, which some people cannot tolerate. The ability to tolerate the taste is an X-linked trait that is dominant to the recessive trait for not being able to tolerate its sweetness. If a hula dancer, who loves the taste of pineapple even though her dad does not, marries a man who also likes pineapple (his dad can’t tolerate it either), what can they expect from their children? Phenotypically explain weather the children will be sitting with their grandfathers or their parents and what kind of kids they will be?

Like problem 6. A woman, notices her child has cut has cut his hand on the coral reef. It briefly bleeds and it reminds her that she needs to have her children’s blood types discovered in case a serious emergency arises. She is type A and her father was type O. She knows her husband is type B and his father was type O. Armed with this knowledge, what can she predict that her child’s blood type might be?

Like problem 7. In a fish tank at the Waikiki Aquarium there are three humuhumu-nukunuku-a-pua'a

Fish. Two male and one female. As the days go by the female becomes pregnant. Fish 1) claims to be the father while Fish 2 is already thinking of naming his proud offspring. The third fish, the female, isn’t talking at all, knowing that she has no idea which of the fish is the father. A baby girl fish is born with no dorsal fin, which is the result of an X-linked recessive condition. Fish 1 has no dorsal fin, Fish 2 does. The proud mother fish has a dorsal fin, and cannot remember what her parents looked like. Is it possible to find out who the proud humuhumu-nukunuku-a-pua'a is?

Like problem 8. In the case of the hibiscus flower, the state flower of Hawaii, the stunning yellow flower is incompletely dominant to the decorative white flower. The heterozygous version of the two produces an eye pleasing pale yellow flower. If we were to cross two of the pale yellow flowers, what kind of garden would we expect?

Like problem 9. Tiger sharks, strong swimming (S) is dominant to weak swimming (s) and having a strong desire to eat geology professor’s (g) is recessive to (G) disliking the taste of geology professors. Give the phenotypic ratios of F1 and F2 for a cross between a weak swimming shark with the appetite for geologists and a homozygous strong swimming shark that does not like to eat geologists (homozygous). What level of fear should Dr. Kubicek (North Lake’s professor of Geology on the Hawaiian Field Studies Program) have if he decides to go in the water?

Like problem 10. The Hawaiian honu, or the pacific green sea turtle, has either the dominant trait (N) to have a normal shell or the recessive (n) where their shell is underdeveloped. They also have the dominant ability (F) to have wedge shaped flippers to the recessive (f ) to have square flippers. Give the expected phenotypic ratio between a honu that has an underdeveloped shell and square flippers with an individual who is heterozygous for both traits.