Channel surfing syndrome. Do you tend to watch one specific thing on TV at a tim

Question

Channel surfing syndrome. Do you tend to watch one specific thing on TV at a time, or do you surf the channels to see what else is on without really watching one thing from beginning to end? If you are one that likes to surf the channels, then you are a channel surfer, whereas if you do not tend to surf the channels, or do not watch TV at all, then you are a non-channel surfer. Let's suppose that channel surfing is a trait controlled by a single gene with just two alleles, "C" and "c," and that the allele "C" (big "C") is completely dominant over the allele "c" (little "c"). Thus, CC and Cc are the two genotypes that code for the dominant phenotype, channel surfer, whereas cc is the genotype that codes for the recessive phenotype, non-channel surfer.

Starbucks trait. Do you visit Starbucks often, perhaps several times during a typical week? If so, then you are a Starbucks fan. Do you rarely go to Starbucks, if at all? Is it your last resort when it comes to getting coffee? That would make you a Starbucks avoider.

Let's suppose that being a Starbucks fan is a trait controlled by a single gene with just two alleles, "R" and "r." The allele "R" (big "R") is completely dominant over the allele "r" (little "r"). Thus, RR and Rr are the two genotypes that code for the dominant phenotype, Starbucks fan, whereas rr is the genotype that codes for the recessive phenotype, Starbucks avoider.

3. Social media trait. Do you check your cell phone for texts, tweets, instagrams, and/or Facebook updates every chance you get, all day long? Do you respond to texts almost immediately after they are received? Do you find yourself spending a lot of your evenings at home catching up on your social media correspondence, and at times find it overwhelming? If you answered yes to one or more of these questions, then you are probably a social media addict. If not, you are a social media non-addict.

Let's suppose that being a social media addict is a trait controlled by a single gene with just two alleles, "A" and "a." The allele "A" (big "A") is completely dominant over the allele "a" (little "a"). Thus, AA and Aa are the two genotypes that code for the dominant phenotype, social media addict, whereas aa is the genotype that codes for the recessive phenotype, non-addict.

1. What would be the expected proportions of genotypes and phenotypes for the offspring of a cross between a woman who is homozygous recessive and a man who is heterozygous for the Starbucks trait?

2. What would be the expected proportions of genotypes and phenotypes for the offspring of a cross between a woman who is heterozygous and a man who is also heterozygous for the social media trait?

3. What would be the expected proportions of genotypes and phenotypes for the offspring of a cross between a woman who is homozygous dominant and a man who is homozygous recessive for the channel surfing syndrome trait?

Explanation / Answer

Answer:

1. The expected proportions of genotypes and phenotypes for the offspring of a cross between a woman who is homozygous recessive and a man who is heterozygous for the Starbucks trait would be as follows:

Cross: Rr x rr

F1: Rr, Rr, rr, rr

a. Genotypes: 50% Rr, 50% rr

b. Phenotypes: 50% fan, 50% avoider

2. The expected proportions of genotypes and phenotypes for the offspring of a cross between a woman who is heterozygous and a man who is also heterozygous for the social media trait:

Cross: Aa x Aa

F1: AA, Aa, Aa, aa

a. Genotypes: 25% AA, 50% Aa, 25% aa

b. Phenotypes: 75% social media addict, 25% non addict

3. The expected proportions of genotypes and phenotypes for the offspring of a cross between a woman who is homozygous dominant and a man who is homozygous recessive for the channel surfing syndrome trait would be as follows:

Cross: CC x cc

F1: Cc

a. Genotypes: 100% Cc

b. Phenotypes: 100% channel surfer

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.