Arrange the following 'relationships to the proband', in descending order with respect to the proportion of genes inherited from the common ancestor- A. Second Cousin B. Half Sib C. Monozygotic twin D. Dizygotic twin Choose the correct answer from the options given below:
Genetic Relatedness Ranking
The question requires arranging specific genetic relationships in descending order based on the proportion of genes inherited from a common ancestor. This order is determined by the degree of genetic relatedness between the individuals involved.
Proportion of Shared Genes Analysis
The standard proportion of genes shared (relatedness coefficient, denoted as $\textit{r}$) for each relationship type is as follows:
- Monozygotic twin (C): Share approximately 100% of their genes ($\textit{r} = 1.0$). They originate from a single fertilized egg.
- Dizygotic twin (D): Share approximately 50% of their genes on average ($\textit{r} = 0.5$). They develop from two separate fertilized eggs, similar to fraternal siblings.
- Half Sib (B): Share approximately 25% of their genes on average ($\textit{r} = 0.25$). They have only one biological parent in common.
- Second Cousin (A): Share approximately 6.25% of their genes on average ($\textit{r} = 0.0625$). Their common ancestors are typically great-grandparents.
Determining Descending Order
To find the descending order, we compare the relatedness coefficients:
- C: $\textit{r} = 1.0$
- D: $\textit{r} = 0.5$
- B: $\textit{r} = 0.25$
- A: $\textit{r} = 0.0625$
Arranging these from the highest proportion to the lowest gives the order: $1.0 > 0.5 > 0.25 > 0.0625$.
Mapping this back to the relationship labels, the correct descending order is C, D, B, A.
Important Questions from Human genetics
Mendel selected which of the following traits for his studies?
Two strains of mice which are genetically identical except for a single genetic locus or region are said to be:
Interacting genes which are involved in producing continuous variation in phenotypes in a population are known as/constitute
Sampling of 200 persons for their ABO blood group was done from an urban area. The types of blood group observed in the given population are as follows:
A = 60, B = 32, AB = 10 and O = 98
Which of the following gives the correct frequency of blood group determining alleles IA , IB and IO in the given population?
The table given below shows the Lod score values of three different pairs of genes studied for assessing if they are linked pairs:
Gene Pair '1' Gene Pair '2' Gene Pair '3' Lod Score 1 2 3 The following conclusions were made from the data given above:
A. For gene pair 1 the probability of the genes being linked is 10 times more likely than them assorting independently.
B. For gene pair 2, the Lod score 2 indicates that the probability of the genes being linked is twice more likely than assorting independently.
C. The genes of pair 1 and 2, can both be considered as linked, while the genes of pair 3 exhibits independent assortment.
D. The genes of pair 3 can be considered as linked.
Which one of the following options represents statement(s) that is/are correct?
