Chapter 4 Blog

1. This process produces gametes,
    4 daughter cells.
    It goes through interphase once,
    but PMAT twice.
    Don't mix it up with another.

WHAT AM I?

2. This is a number,
    out of another number,
    after the integer,
    it has two dots and a slash,
    and it is a simple math term.

WHAT AM I?

3. This is a polygon,
    but no ordinary one.
    It is separated into 4 sections,
    and is used to find,
    the offspring's possible genotypes.

WHAT AM I?

4. This one is weaker than the other,
    always being masked.
    The other is always shown,
    unless this has
    a clone of itself.

WHAT AM I?

5. This is the proper way,
    of passing on genes.
    Genes to the offspring,
    from the mother and father,
    and this gives me my characteristics.

WHAT AM I?


ANSWERS
1. Meiosis
2. Percentage
3. Punnett Square
4. Recessive
5. Heredity

Heredity Word Problem

Red hair is recessive (r), while blond hair is dominant (R). If a red-haired woman marries a blond-haired man, what are the possible genotypes of the parents if 100% of their children will be blonde? Please show your work through a Punnett Square.

Known information:

Blond hair = dominant
Red hair = recessive

The red-haired woman's genotype has to be rr, since blond hair is dominant (recessive alleles require 2 copies of it to show in the phenotype).

The blond-haired man's genotype can either be Rr, or RR.

Rr:     ___r_______r___

     R |__Rr___|__Rr___|            With Rr, 50% will have blond hair, while 50% will have red hair.

     r  |__rr____|___rr___|  

RR:   ___r_______r___

     R |__Rr___|__Rr___|            With RR, 100% will have blond hair.

     R |__Rr___|__Rr___|  

Therefore, the genotypes of the parents are rr (red-haired woman) and RR (blond-haired man). RR x rr

His genotype is Rr, and the dominant allele is expressed in his phenotype, which is having blond hair.

*I made up the genotype of the blond-haired boy in the picture so it would fit in with the problem.