For a certain trait, Steve has the alleles Gg, and Bree has the alleles gg.
Steve and Bree has six children, and all of the children have the alleles gg. Explain how this could happen.
Although it is only 25% chance of having gg, it is unlikely (.25^6) to occur in real life, but it can.
In order to understand how all six children of Steve and Bree have the alleles gg, let's review some basic genetics principles.
Every individual inherits two copies of each gene, one from each parent. These copies of a gene are called alleles. Alleles can be dominant or recessive. In this case, we are considering a certain trait, and the alleles for this trait are G and g.
The letter G represents the dominant allele, while the letter g represents the recessive allele.
Steve has the alleles Gg, meaning he has one dominant (G) and one recessive (g) allele for the trait. Bree, on the other hand, has two recessive alleles (gg) for the trait.
When Steve and Bree have children, each child has a 50% chance of inheriting Steve's G allele and a 50% chance of inheriting Bree's g allele for the trait. This is because Steve can pass either his G or g allele, while Bree can only pass her g allele.
Now let's consider how this would play out for their six children. Since both Steve and Bree only have the recessive g allele, all their children will inherit the g allele from both parents.
Therefore, all six children will have the alleles gg for the trait, as they have received the g allele from both Steve and Bree.
In conclusion, the reason why all six children have the alleles gg is because both parents only have the recessive g allele for the trait, and each child has a 100% chance of inheriting this allele from both parents.
To understand how this could happen, it is important to have a basic understanding of genetics and how alleles are inherited. In humans, traits are often determined by genes, which are segments of DNA that collectively define specific characteristics. Each gene can have various versions known as alleles.
In this case, Steve and Bree both have alleles for a certain trait: Steve has the alleles Gg, while Bree has the alleles gg. The uppercase G represents a dominant allele, while the lowercase g represents a recessive allele for the trait.
When two individuals reproduce, each parent randomly passes on one allele for each gene to their offspring. The combination of alleles from each parent determines the traits expressed in the children.
Based on the information given, all six of Steve and Bree's children have the alleles gg. This means that each child has inherited a recessive g allele from both Steve and Bree.
To have children with gg alleles only, both parents must have at least one g allele to pass on. Steve has the genotype Gg, meaning he has one dominant G allele and one recessive g allele. On the other hand, Bree has the genotype gg, which means she has two recessive g alleles.
When reproducing, Steve has a 50% chance of passing on his dominant G allele and a 50% chance of passing on his recessive g allele to each child. However, since all the children have the gg genotype, it can be inferred that Steve has consistently passed on the recessive g allele in each case.
Therefore, each child receives one g allele from Steve and one g allele from Bree, resulting in all children with the gg genotype for the particular trait.
In summary, all six children having the gg genotype can occur when both parents have at least one recessive g allele and consistently pass it down to their offspring during reproduction.