Application of Mendel's First Law

Two animals heterozygous at gene A are mated. What ratio of genotypes will be produced in the offspring? 3:1 2:1:2 1:1 1:2:1 2:1

1:2:1 The Punnett square shows that the ratio is 1:2:1, meaning that 1/2 will be Aa, while 1/4 AA and 1/4 will be aa.

What is the phenotypic ratio for monohybrid cross?

3:1 dominant to recessive

What is a punnet square?

A chart that shows all the possible combinations of alleles that can result from a genetic cross Help us see the genotypic ration

What is a monohybrid cross?

A cross between two heterozygous organisms

Based on the genotypic ratio what can also be predicted?

A phenotypic ratio

Sarah has blonde hair even though both of her parents have brown hair. In old photos, she has seen that both her maternal grandmother and paternal grandmother had blonde hair before it went white. Given this information what can you suggest about the dominance of the different hair color genes? Brown is dominant, blonde is recessive. Blonde is dominant, brown is recessive. White hair is dominant over brown and blonde. Brown and blonde are both recessive. Brown and blonde are equally dominant.

Brown is dominant, blonde is recessive. Since both of her parents have brown hair but each had a mother with blonde hair, both of her parents would be heterozygous for hair color. It can be concluded that brown is a dominant gene and blonde is a recessive gene and Sarah got a recessive color gene from each of her parents.

What is a true breeding strain?

Organism that will always produce offspring the same as the parents

The organisms in the initial step in a series of genetic crosses are known as the _____. F1 Generation P1 Generation P Generation F2 Generation

P Generation

What is the offspring of the P generation referred to?

The first filial, or more commonly, F1 generation

A scientist is studying an animal which can be found with either black or white fur. Which of following could be FALSE in this study? Mating the animal with black fur to another animal with black fur produces both black and white animals. The genotype of all the animals, with black or white fur, is BB. Mating an animal with black fur with an animal with white fur produces animals with white fur. The genotype of an animal with white fur is bb. The genotype of an animal with black fur is Bb.

The genotype of all the animals, with black or white fur, is BB.

What is the P generation?

The organisms used in the initial cross in a series of genetic crosses

What are the organism in the P generation called?

True breeding

What is the genotypic ratio for monohybrid cross?

homozygous dominant: heterozygous: homozygous recessive 1:2:1