Which of the following is not a feature of Down's Syndrome?

1. It is caused by a non-disjunction in an autosome

2. The affected individual has trisomy of chromosome 21

3. The aflected individual has a characteristic simian palmar crease

4. The mental development of affected individual is normal

Identify the incorrect statement:

(1) In addition to recombination, mutation is another phenomeonon that leads to variation in DNA.

(2) Chromosomal aberrations are commonly observed in cancer cells.

(3) A classical example of a point mutation is sickle cell anaemia.

(4) Non ionising radiations cannot be mutations. 

Pedigree analysis is resorted to for genetic analysis in humans rather than conventional genetic methods because:

I. Choice matings are not possible

II. Number of progeny is limited

Of the two statements:

(1) Only I is correct

(2) Only II is correct

(3) Both I and II are correct

(4) Both I and II are incorrect

Match each item in Column I with one item in Column II and chose your answer from the codes given below:

1. I - v; II - vii; III - iii; IV - i

2. I - iv; II - vi; III - iii; IV - i

3. I - v; II - vi; III - iii; IV - ii

4. I - v; II - vi; III - iii; IV - i

In a monohybrid cross F₁ progeny resemble neither of the parents. What would be true in this case?

1. The parental traits would not appear in any of the F₂ -progenies

2. The F₂ phenotypic ratio will be different from the F₂ genotypic ratio

3. It could be a case of incomplete dominance

4. The F₂ phenotypic ratio will be similar to any Mendelian monohybrid cross

The two alleles of a gene pair are located on:

1. Homologous sites on homologous chromosomes

2. Heterologous sites on homologous chromosomes

3. Homologous sites on heterologous chromosomes

4. Heterologous sites on heretologous chromosomes

Male heterogamety is not seen in:

1. Humans

2. Melandrium album

3. Birds

4. Fruit fly

The trait shown in the given pedigree chart is most likely a/an:

1. Autosomal recessive trait

2. Autosomal dominant trait

3. Sex linked recessive trait

4. Sex linked dominant trait

Aneuploidy results from :

1. Point mutations

2. Gross structural changes in chromosomes

3. Failure of cytokinesis after telophase stage of cell division

4. Failure of segregation of chromatids during cell division 

Which of the following are correct regarding linked genes?

I. are located near each other on the same chromosome.

II. violate the law of independent assortment

III. segregate together during meiosis

(1) Only I and II

(2) Only I and III

(3) Only II and III

(4) I, II, III