Question

punnett squares practice
introduction
a punnett square helps scientists predict the possible genotypes and phenotypes of offspring when they know the genotypes of the parents. the phenotype is the physical appearance of an organism and the genotype is the inherited combination of alleles. this skill sheet will give you additional practice in using punnett squares to solve genetics problems.
example
in rabbits, black fur is dominant to white fur. if you cross a bb male with a bb female, what are the possible genotypes and phenotypes of the offspring? what is the percent chance for each type?
punnett square and table image omitted
punnett square practice

1. in cabbage butterflies, white wings are dominant to yellow wings. if a ww butterfly is crossed with a ww butterfly, what are the possible genotypes and phenotypes of the offspring and the percent chance for each?

punnett square and table image omitted

1. in dogs, there is a hereditary type of deafness caused by a recessive gene. two dogs who carry the gene for deafness (d) but have normal hearing are mated. what are the possible genotypes and phenotypes of their offspring and the percent chance for each?

punnett square and table image omitted

Explanation:

Paso 1: Analizar el problema 1

Padres: $Ww$ (ala blanca) y $ww$ (ala amarilla). Los alelos del padre $Ww$ son $W$ y $w$, los del padre $ww$ son $w$ y $w$. Se llena el cuadro de Punnett:

$$\begin{array}{c|cc} & W & w \\ \hline w & Ww & ww \\ w & Ww & ww \\ \end{array}$$

Paso 2: Calcular proporciones del problema 1

Contar combinaciones: 2 $Ww$ y 2 $ww$. La proporción de cada genotipo es $\frac{2}{4}=50\%$. El alelo $W$ (ala blanca) es dominante, así que $Ww$ tiene fenotipo de alas blancas, $ww$ de alas amarillas.

Paso 3: Analizar el problema 2

Padres: ambos $Dd$ (audición normal, portadores de sordera recesiva). Alelos de cada padre: $D$ y $d$. Se llena el cuadro de Punnett:

$$\begin{array}{c|cc} & D & d \\ \hline D & DD & Dd \\ d & Dd & dd \\ \end{array}$$

Paso 4: Calcular proporciones del problema 2

Contar combinaciones: 1 $DD$, 2 $Dd$, 1 $dd$. Las proporciones son $\frac{1}{4}=25\%$ para $DD$, $\frac{2}{4}=50\%$ para $Dd$, $\frac{1}{4}=25\%$ para $dd$. El alelo $D$ (audición normal) es dominante, así que $DD$ y $Dd$ tienen fenotipo de audición normal, $dd$ de sordera.

Answer:

1.

Genotype	Phenotype	Chance
$ww$	Yellow wings	50%

2.

Genotype	Phenotype	Chance
$Dd$	Normal hearing	50%
$dd$	Deaf	25%