In which of the following, you CANNOT determine the genotype of the individual f
ID: 259195 • Letter: I
Question
In which of the following, you CANNOT determine the genotype of the individual from his/her phenotype directly and with certainty?
A childless unaffected individual in an AD pedigree with incomplete penetrance
Incomplete dominance
XLR in males
Y-linked traits
The recessive phenotype of a Mendelian trait.
An unaffected teenage child of an affected individual with Huntington (AD)
Two of the above
The law of segregation does not apply for three genes (A, B and C) if all of them:
have two alleles displaying codominance
have two alleles displaying incomplete dominance
are located in mitochondrial DNA
have more than two alleles in the population
are located on one chromosome
A.A childless unaffected individual in an AD pedigree with incomplete penetrance
B.Incomplete dominance
C.XLR in males
D.Y-linked traits
E.The recessive phenotype of a Mendelian trait.
F.An unaffected teenage child of an affected individual with Huntington (AD)
G.Two of the above
Explanation / Answer
1) Option A is the correct answer.
In the following case, A childless unaffected individual in an AD pedigree with incomplete penetrance, genotype cannot be directly determined from his/her phenotype and with certainity. Incomplete dominance is the hereditary case in which less than 100% individuals with the particular genotype have an observable effect of the genotype. It may give rise to phenomenon known as "skipping of a generation in a family with a well-known autosomal dominant disorder." As such, it will not be possible to detrmine the genotype in such a case with certainity just from knowing the phenotype.
2) Option E is the correct answer.
If the genes are located on one chromosome. it may cause non-disjunction of chromosome during meiosis due to which genes may move to a common gamete violating law of segregation.