Punnett Squares
Complete a Punnett square for TT and tt.
Tt, Tt, Tt, Tt
Jimmy has a big nose. His genotype is GG. Sally also has a big nose. Her genotype is Gg. What is the possibility that their children could have a small nose?
GG, GG, Gg, Gg
0%
___________ is the passing down of traits from one generation to the next.
Heredity
Determine the phenotype: Widows peak (W) is dominant over not having a widows peak (w).
WW:
Ww:
ww:
WW, Ww: Widows peak
ww: No widows peak
The method or tool we use today to predict the traits of offspring is a ________________ .
Punnett Square
Complete a Punnett square for Gg and Gg.
GG, Gg, Gg, gg
Jared is heterozygous for brown hair. His wife is homozygous for blonde hair. Brown hair is dominant to blonde hair. What is the chance that their children will take after their mom? dad? Use B as the allele.
Bb, Bb, bb, bb
50% chance to take after Mom.
50% chance to take after Dad.
A pair of alleles that are the identical are called __________________.
homozygous
HH, TT, zz. Each of these are ______________________.
Homozygous
Capital letters are always represented by the _____________ allele, not the recessive allele.
dominant
Complete a Punnett square someone who is heterozygous for tall and for someone who is homozygous for short.
Tt, Tt, tt, tt
Use S for the allele. SpongeBob Square pants recently met SpongeSusie Roundpants at a dance. SpongeBob is heterozygous for his square shape, but SpongeSusie is round. Create a punnett square to show the possibilities that would result if SpongeBob and SpongeSusie had children.
What are the chances of a child with a square shape? ________ out of ________ or ________%
What are the chances of a child with a round shape? ________ out of ________ or ________%
What are the chances of a child with a square shape? 2 out of 4 or 50%
What are the chances of a child with a round shape 2 out of 4 or 50%
A pair of alleles that are different are called ____________________.
heterozygous
Jim and Jane are both heterozygous for being tall. What are the chances that they will have a short child?
25% chance
This allele shows up every time it is present.
Dominant
Complete a Punnett square for someone who is Homozygous for green eyes and someone who has blue eyes. Green is dominant over blue. Use G as the allele.
Gg, Gg, Gg, Gg.
Tim and Jenny both have dark skin, but each of them carry a recessive trait for light skin. What are the chances that their children will have dark skin? Light skin? Use S for the allele
75% dark skin
25% light skin
___________________ describes a pair of alleles and is represented by letters such as Tt or TT.
genotype
GG, Gg, Gg, gg. Green eyes are dominant to blue eyes. What percent have green eyes? What percent have blue eyes?
Green Eyes: 75%
Blue Eyes: 25%
This trait can only be shown when it is paired with an identical allele.
Recessive
The four answers for a Punnett square are Zz, Zz, zz, zz. What are the genotypes for the parents?
Zz and zz.
James is heterozygous for big lips. His wife also has big lips, but one of their children has small lips. What is his wife's genotype? Use L as an allele.
Ll
__________________ is simply the expression of the genotype. It is how the trait is expressed (ie. dark hair, tall, big lips, etc.)
phenotype
What does a Punnett square show?
The possible outcomes of a genetic cross.
He is the father of modern genetics.
Gregor Mendel