DNA and Genetics - Chapter 4

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

Monohybrid cross

Monohybrid cross = cross where you look at only one trait

The flowers cross. That means they are the parents, which we call the P-generation.

Both flowers are homozygous. White is recessive What are their genotypes?

And what is the genotype and the phenotype of the offspring?

Monohybrid cross

Monohybrid cross = cross where you look at only one trait

The flowers cross. That means they are the parents, which we call the P-generation.

Both flowers are homozygous. White is recessive What are their genotypes?

Red flower = BB         White flower = bb

And what is the genotype and phenotype of the offspring?

Genotype = Bb         Phenotype = red

Monohybrid cross

The F1 generation is the offspring for the P-generation.

The F2-generation is the offspring of the F1-generation.

Now, the F1 flowers will cross. Make a Punnett-square of this cross. What percentage of the F2 will be white?

25% will be white

	A	a
A	AA	Aa
a	Aa	aa

Monohybrid cross

The F1 generation is the offspring for the P-generation.

The F2-generation is the offspring of the F1-generation.

Now, the F1 flowers will cross. Make a Punnett-square of this cross. What percentage of the F2 will be white?

Black fur(B) in guinea pigs is dominant over white fur(b). Find the probability of heterozygous offspring in the cross: BB x Bb.

Black fur(B) in guinea pigs is dominant over white fur(b). Find the probability of a white offspring in a cross: Bb x bb

A woman with blue eyes has a child with brown eyes. The allele for B brown eyes is dominant over the allele for blue eyes. What genotype(s) could the father have had?

In cats, the gene for a spotted coat (R) is dominant over that for an unspotted coat (r). A female with spotted fur gives birth to a male with spotted fur. Among the young are animals with a spotted coat and animals with an unspotted coat. What are the genotypes of the parent animals?