Vocabulary
A characteristic such as hair color in humans or seed color in peas is called
trait/if it is visible we say phenotype
List the possible percentages on a Punnett Square. (there are 5)
100%
75%
50%
25%
0%
The likelihood a child will have the recessive trait when two heterozygous parents are crossed.
bb-25%
Curly hair is the dominant allele for texture. What are the possible genotypes?
CC or Cc
Gregor Mendel is known as ...
What two terms can be used to describe the genotype
bb?
Homozygous recessive or
purebred
Cross two heterozygous parents. What is the probability of having an offspring with the dominant phenotype?
3/4 or 75%
BB, Bb, Bb
NOT bb-that would be recessive!
One dog is purebred for long ears. The other is hybrid for short ears. What is the probability of having puppies with short ears?
50%
Green Spots are the recessive alleles in frogs. What are the possible genotypes?
Peas (Yip-pea)
Hybrid OR
Heterozygous
Cross a homozygous dominant pea plant that is tall with a heterozygous pea plant. What are the chances of the offspring being tall?
100% (Right away you should have seen the homozygous dominant parent would give one capital letter to each offspring, causing the dominant trait to be visible.)
The likelihood a child will have the recessive phenotype when one parent is hybrid and the other is purebred for the recessive trait.
50% bb
Star shaped eyes are dominant. What are the possible genotypes?
SS or Ss
Mendel first crossed Purebred tall pea plants (TT) with purebred short pea plants (tt) and noticed all of the plants were...
Tall (Tt)
What two terms can be used to describe the genotype BB
Homozygous dominant OR
purebred
In guinea pigs the dominant the allele for black fur (B) is dominant over the allele for white fur (b). In a cross between a heterozygous black guinea pig and a homozygous recessive white guinea pig, what percent of the offspring will have white fur?
50% (bb)
Sickle cell anemia is a recessive genetic disease. If both parents are carriers, what is the chance they will have a child with the disease?
25% bb
The phenotype of two XX chromosomes.
female
Then he took the offspring from the P(arent) generation (Tt) and crossed them together. He noticed the offspring were...
25% short (tt) and 75% tall (TT or Tt)
Could the genotypes BB, Bb and bb have the same phenotype? Why or Why not?
NO!!! BB and Bb will be dominant (at this level) but bb will carry the recessive trait, as there is no dominant letter to mask the recessive trait.
In rabbits, the allele for a spotted coat is dominant for the allele for a solid colored coat. A spotted rabbit was crossed with a solid colored rabbit. The offspring all had spotted coats. What are the probable genotypes for the parents?
Spotted Coat Rabbit-BB
Solid Coat Rabbit-bb
**There was at least one B in each genotype in the offspring squares!
One parent is homozygous dominant. The other parent is heterozygous. List all the possible genotypes their offspring could be.
BB, Bb
What is the genotype for a male?
XY
Basically, this showed.....
The recessive trait or allele is not lost. It can show up in future generations.