Whether a trait is dominant or recessive DOES NOT have anything to do with how common it is.

Eg – straight hair is the most common type in Asia, but it is a recessive genotype.

Whether a trait is dominant or recessive DOES NOT have anything to do with how common it is. Eg – straight hair is the most common type in Asia, but it is a recessive genotype. In inheriting a trait: -Two recessives crossed can produce only recessive offspring.

Whether a trait is dominant or recessive DOES NOT have anything to do with how common it is. Eg – straight hair is the most common type in Asia, but it is a recessive genotype. In inheriting a trait: -Two recessives crossed can produce only recessive offspring. -Two dominants crossed can produce both dominant and recessive offspring if both parents are heterozygous.

Whether a trait is dominant or recessive DOES NOT have anything to do with how common it is. Eg – straight hair is the most common type in Asia, but it is a recessive genotype. In inheriting a trait: -Two recessives crossed can produce only recessive offspring. -Two dominants crossed can produce both dominant and recessive offspring if both parents are heterozygous. Complete activity 2D

Individuals which are heterozygous may be called carriers, because they carry the recessive allele which is masked by the dominant allele so is not expressed in the phenotype.

For breeding purposes, heterozygotes are not desirable because the recessive can pair up and create a recessive offspring – therefore they are NOT pure breeders

Individuals which are heterozygous may be called carriers, because they carry the recessive allele which is masked by the dominant allele so is not expressed in the phenotype. For breeding purposes, heterozygotes are not desirable because the recessive can pair up and create a recessive offspring – therefore they are NOT pure breeders Animal breeders often need to find out whether an individual showing the dominant phenotype is homozygous (pure-breeder) or heterozygous.

Individuals which are heterozygous may be called carriers, because they carry the recessive allele which is masked by the dominant allele so is not expressed in the phenotype. For breeding purposes, heterozygotes are not desirable because the recessive can pair up and create a recessive offspring – therefore they are NOT pure breeders Animal breeders often need to find out whether an individual showing the dominant phenotype is homozygous (pure-breeder) or heterozygous. To find this out, the individual is crossed with a homozygous recessive individual.

Rabbits may have brown hair or white hair. Brown is dominant (therefore may be BB or Bb) – but we can’t tell. White hair is recessive (therefore bb)

Firstly we cross Bb x bb This shows that 50% will be brown and 50% white so parent is not pure breeding. Bb bBbbb bBbbb

Now we try again Cross BB x bb All offspring are brown = this parent can be used for breeding. *Now complete 2E* BB bBb b