Fruit colour in squash in an example of: 
A man whose father was colour blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour blind?
Colour blindness is X-chromosome-linked character.
As color blindness is an autosomal recessive genetic disorder, for it is present at X -chromosome. Thus, according to the situation given in the question, a man whose father was color blind (will be, i.e, XY normal) marries a woman whose mother was color blind and father was normal (i.e, this woman will be a carrier) according to the cross given in the first figure.
Thus, when marriage will happen between a normal man and a carrier woman, in that case, the percentage of a male child to be colorblind is 25% (this can be easily observed from the second figure).
In a population of 1000 individuals 360 belong to genotype AA, 480 to Aa and the remaining 160 to aa. Based on this data, the frequency of allele A in the population is: 
According to Hardy-Weinberg equilibrium,
p2 + 2pq + q2 = 1
where p2 is the frequency of homozygous genotype AA
q2 is the frequency of genotype aa
pq is the frequency of genotype Aa
There are 1000 individuals, out of which 360 belong to genotype AA.
p2 = 360/1000 = 0.36
Then p = 0.6.
So, the correct answer is '0.6'.
If two pea plants having red (dominant) coloured flowers with unknown genotypes are crossed, 75% of the flowers are red and 25% are white. The genotypic constitution of the parents having red coloured flowers will be:
How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments ? [2015 RS]
Seven pairs of contrasting characters were selected in pea plant and studied by Mendel in his experiment.
Which is the most common mechanism of genetic variation in the population of sexually reproducing organism? [2015 RS]
The most common cause of variations is recombination in the organism which are reproduced by sexual way.
Alleles are : [2015 RS]
Alleles are defined as alternative form of same gene.
In his classic experiments on pea plants, Mendel did not use: [2015 RS]
Mendel used seven pea plant traits in his hybridization experiments, which include flower colour (purple or white), flower position (axil or terminal), stem length (long or short), seed shape (round or wrinkled), seed colour (yellow or green), pod shape (inflated or constricted), and pod colour (yellow or green). Pod length is not included.
In the following human pedigree, the filled symbols represent the affected individuals. Identify the type of given pedigree. [2015 RS]
A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colour blind?
Conditions of a karyotype 2n +1, 2n –1 and 2n + 2, 2n – 2 are called:
Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s), called aneuploidy. Aneuploidy arises due to non-disjunction of homologous chromosome.
Aneuploidy is of four types:
Which of the following most appropriately describes haemophilia ? 
A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of: 
Phenotypic ratio : 3: 1 (Tall :Dwarf) Genotypic Ratio: 1:2:1 (Homozygous Tall : Heterozygous Tall : Dwarf)
Match the terms in Column-I with their description in Column-II and choose the correct option :
So, Option B is correct.
Pick out the correct statements : 
(a) Haemophilia is a sex-linked recessive disease.
(b) Down's syndrome is due to aneuploidy.
(c) Phenylketonuria is an autosomal recessive gene disorder.
(d) Sickle cell anaemia is a X-linked recessive gene disorder.
In a testcross involving F1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates ______. 
A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of chromosomes as compared to other dividing cells. This would result in: