Maria carries two genes for brown eyes (BB), and John carries two genes for blue eyes (bb). (Assume that BROWN dominates over blue). Their child will have a:

Their child will have brown eyes because brown allele is dominant.

Explanation:

Eye Color

- Brown eyes B

- Blue eyes b

Purebred individual with brown eyes (BB)

- Homozygous

Purebred individual with blue eyes (bb)

- Homozygous

Hybrid individual with brown eyes (Bb)

- Heterozygous

Eye Color

- Mother is (BB)

- Father is (bb)

Their Genes Are Crossed

- BB x bb

- Since we are looking at only 1 gene, it is called a monohybrid cross.

Law of Segregation

- Alleles for the same trait must be in separate sex cells.

- Mother is (BB) as his diploid genotype

- Father is (bb) as her diploid genotype

Somatic Cells BB bb

Sex cells B B b b

So according to the punnett square.

B b b

Bb Bb

B Bb Bb

Bb shows that the child will have brown eyes as B allele is dominant over b allele.

Bb = Brown

All of the offspring will have brown eyes, but they will be heterozygous

individuals