In humans, earlobes that are suspended are dominant over those that are attached. If a mother has suspended earlobes (but her mother did not) and the father has attached earlobes, what are the chances that their first child will have attached earlobes What about the fourth child?draw a graph.
Answers
Answer:
Genotype of mother = Ee (heterozygous dominant
Genotype of father = ee (homozygous recessive)
Punnet square ( look at the attached picture)
Thus there is 50 percent chance of the first and last child ( any child) being born with attached earlobes
Explanation:
Dominant traits (free earlobes) are traits which can be manifested in an individual containing one (heterozygous) or both (homozygous) alleles of the particular trait. Such dominant alleles are denoted using capital letters.
Recessive traits (attached earlobes) are those traits which are manifested in an individual only when both alleles (homozygous) of that particular trait is present. Such recessive alleles are denoted using small letters.
In this case, the free earlobes is a dominant trait which means the genotype of the mother can be heterozygous dominant (Ee) or homozygous dominant (EE) (Note that the letters used to denote alleles can be of your wish)
Looking at the grandmothers phenotype we can determine the exact genotype of mother because earlobe inheritance follows Mendel inheritance pattern. The grandmother did not have free earlobes (she had attached earlobes which is a recessive trait) and her genotype would be ee (homozygous recessive).
Now genotype of mother is either Ee or EE where as genotype of grandmother is ee. Since mother would have received one allele for earlobe from grandfather and another allele for earlobe from grandmother, we can be sure that mother has received recessive allele 'e ' from grandmother. (Because grandmother has only recessive alleles in her genotype). By this we can conclude the genotype of mother.
Now genotype of mother = Ee and genotype of father = ee (earlobes attached is a recessive trait.
By monohybrid cross we get genotypes of kids as Ee, ee, ee and Ee, which means 50 percent of offspring have earlobes suspended (Ee) and 50 percent of offspring have earlobes attached (ee)
Therefore there is 50 percent chance of first and fourth child being born with attached earlobes. (In fact any child for this couple would have 50 percent chance of having attached earlobes and 50 percent chance of having free earlobes)
Answer:
Required Answer :-
The graph
Hence we say that their is half chances that the first child and fourth child will have earlobes