Which dominant trait is the most common in our class?

Which dominant trait is the most common in our class?

Which dominant trait is the most common in our class? 150 150 Nyagu

Question Description
I’m working on a biology question and need an explanation to help me understand better.

Use the following descriptions to fill out the table on the next page about yourself.

A.The ability to roll the tongue into a u-shape is dominant over the lack of this ability.

B.Having a widow’s peak (your hairline comes to a point in the center of your forehead) is the dominant phenotype. No widow’s peak (a straight hairline) is recessive.

C.A free, detached earlobe is the dominant phenotype. Attached earlobes are recessive.

D.Hitchhiker’s thumb (being able to bend your thumb joint backwards) is the recessive phenotype. No hitchhiker’s thumb (thumb can only bend back until it is straight) is dominant.

E.Bent little finger (the top joint of your little finger is bent towards your ring finger) is the dominant phenotype. A straight little finger is recessive.

F.Having any hair on your mid-digit (the middle section of your finger; between the section with your nail and the section where you wear a ring) is the dominant phenotype. No mid-digital hair is recessive.

G.Having dimples (of any size on one or both sides) is the dominant phenotype. No dimples is recessive.

H.Second toe longer than the big toe is dominant. Second toe shorter than the big toe is recessive.

I.The presence of freckles is dominant over the absence of freckles.

J.Short index finger means that your index finger is shorter than your ring finger. This may be a sex-influenced trait. In males, short index finger is dominant; in females, long index finger is dominant.

Table 1. Circle your genotype and calculate the class percentages of each phenotype.



Class Percentages

1.Tongue rolling, not rolling

A- aa

2.Widow’s peak, straight hairline

B- bb

3.Earlobes free, attached

C- cc

4.Straight thumb, hitchhiker’s thumb

D- dd

5.Bent little finger, straight finger

E- ee

6.Mid-digital hair, lacking

F- ff

7.Dimples present, absent

G- gg

8.Big toe shorter, longer

H- hh

9.Freckles present, absent

I- ii

10.Roman nose, straight nose

J- jj

11.Curly, wavy, straight hair


12.Dark eyes, light eyes

M- mm

13.Normal vision, red-green colorblind

XN- XnXn XnY

1.Which dominant trait is the most common in our class?

2.Which dominant trait is the rarest in our class?

Part 2: In this exercise, you will pair up with another person in class and “create” two children.

Refer to Table 1 for your genotypes and your partner’s genotypes.

oIf your genotype for a trait in Table 1 is “A-,” then record your genotype is heterozygous in Table 2. In other words, if you have the dominant phenotype, then assume you have the heterozygous genotype.

Record the alleles in the appropriate columns in Table 2.

Pass down an allele from each parent onto each child. For heterozygous genotypes, toss a coin to determine which allele gets passed on to the child.

Record the child’s genotype and phenotype. Repeat for Child #2.

Table 2. Simulation on determining the genotypes and phenotypes of your children.


Your Genotype

Partner’s Genotype

Child #1 Genotype

Child #1 Phenotype

Child #2 Genotype

Child #2 Phenotype


Allele 1 (Heads)

Allele 2 (Tails)

Allele 1 (Heads)

Allele 2 (Tails)