How do you calculate a phenotype or genotype ratio?

Answer 1

If a couple has a black baby, but the father is white and the mother is white, how would you draw the punnet square for the baby?

In this example, white would be the dominant characteristic (W) and black the recessive (w) and both parents would have to be carrying the recessive allele. (The big W stands for the dominant and the w for the recessive alleles.) The punnet square would then look like the following:

NB: Parent 1 and 2 both have the genotype Ww, because they carry both a dominant and a recessive allele.

___ W ____ w ___

W | WW | Ww

w | Ww | ww

Resulting in the phenotype (physical appearance) ratio:

3/4 - White, 1/4 - Black

And the genotype (combination of alleles) ratio:

1/4 - WW, 2/4 - Ww, 1/4 - ww

NB: The dominant allele always shows up when present - the recessive only when two 'little' (lower case) alleles are present.

Answer 2

You do it by using a Punnett Square.

For example- if two mice breed and have the traits Bb and BB (B= brown hair and b=black hair) then you can determine it like this:

B B

B BB BB

b Bb Bb

The parent genes go on either side, and are pulled down one at a time to determine the possibilities. Then, to figure out the ratio, you can just look at the possibilities.

There is 100% chance of their offspring having brown hair~

50% chance of the offspring having both dominant genes,

and 50% chance of them being heterozygous and having one of each gene (though dominant will overpower and they'll have brown hair anyways)

Answer 3

Simple calculations can be done using a punnet square if the genetics of the parents are known.

If the offspring are being examined the phenotypic ratio can be calculated by observation. Genotype can be more problematic. Homozygous recessive traits will have an obvious phenotype with a matching genotype. Determining which offspring are heterozygous that are phenotypically dominant can be done by back crosses on

homozygous recessive mates.

If both the parents and the offspring can be examined...the observer may be able to determine parental genetics and therefore the potential genetics of the offspring more readily. The observer must keep in mind that any genotypic ratios will not be truly known without additional breeding trials.

Answer 4

Snow White was the first of the Disney princesses, and while she lacks some of the elegance of later princesses, she remains an incredibly appealing character, with her sweet disposition endearing her to audiences of all ages. Snow White has a fairly distinctive look, so if you follow Disney's model, most people are likely to recognize the costume even if you don't buy an official costume from Disney.

The first element to Snow White is her yellow skirt. This can be a part of a dress or a separate item. Along with the yellow skirt, you have a blue top. This should be a deep, regal shade of blue, and the sleeves should be puffed and of a different color. This varies, but most costumes incorporate red and silver stripes on the sleeve puffs, which are the most royal looking elements of the costume.

Snow White lives as a peasant for the majority of the story despite her royal blood, so she doesn't wear a crown. Instead, she sometimes wears a simple red bow in her hair, and this will do fine for a costume. Additionally, Snow White's hair is short, so girls with long hair might want to consider putting it up.

While this is a very popular costume for children, it can be great for adults as well, especially if they wear it in conjunction with several children. It could be a family affair, with a mother dressed as Snow White and each child dressed as one of the dwarfs. The dad, meanwhile, could dress as Prince Charming, complementing the princess perfectly. You don't need to have seven children to make this costume work; you can simply pretend that some of the dwarfs are elsewhere for the time being. For added fun, the children can adopt the distinctive characteristics displayed by the dwarfs they are portraying, whether that involves sneezing, laughing frequently or making snarky remarks.

On its own, a Snow White costume is a great choice for Halloween, but in conjunction with several other people, it can be an incredibly fun and memorable costume that will have people talking for days afterward.

Answer 5

To calculate a phenotype or genotype ratio, you need to first determine the possible combinations of alleles that can occur based on the genetic cross you are considering. Then, you can use Punnett squares or probability rules to calculate the ratio of different phenotypes or genotypes that are expected to result from the cross. Each ratio represents the relative frequencies of different traits in the offspring population.