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:
Column I Disorder |
Column II Feature |
I. Phenylketonuria II. Sickle Cell anemia III. Down's Syndrome IV. Turner's Syndrome |
(i) Rudimentary ovaries (ii) Gynecomastia (iii) Trisomy 21 (iv) Lack of enzyme PAH (v) Lack of tyrosinase (vi) Mutation GAG to GUG (vii) Mutation GUG to GAG |
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