Question

1. Define deletion, duplication, inversion and translocation and give examples (6 points) 2. A diploid corn plant has 12 chromosomes. How many total chromosomes would you expect in the following com plants? (3 points) A. Trisomy 7 = B. Tetraploid = C. 3n- D. Monosomy 5 = E. 4n+1 = F. Trisomy 1 and Monosomy 2 = 3. Describe two different experimental strategies to create an allotetraploid from two different diploid species of plants (4 points) 4. Three genes are located on the same chromosome and are known to be 8 mu apart between A and B, and 12 mu apart between B and C. The heterozygous AaBbce genotype individuals were crossed to homozygous recessive aabbce genotype individuals (test cross) and observed 3 double crossover offsprings. If this cross produces a total of 600 offsprings, what are the expected numbers of double crossover offsprings and calculate the Interference (1) value. (3 points) 5. Two genes are located on the same chromosome and are known to be 10 mu apart. An AABB individual was crossed to an aabb individual to produce AaBb offspring. The AaBb offspring were crossed to aabb individuals. (4 points) A) If this cross produces 500 offsprings, what are the predicted numbers of offspring with each of the four genotypes: AaBb Aabb aaBb- and aabb- B) If the parental genotype had been AAbb and aaBB instead of AABB and aabb, what would be the predicted numbers of offspring with each of these four genotypes: AaBb= Aabb= aaBb= and aabb= ?

Answer 1

Normal sequence of genes on the chromosomes-

A B C D E F G H

1. DELETION- A process of chromosomal mutation in which one of the genes get deleted.

ACDEFGH

2. DUPLICATION- When a segment of genes gets duplicated and gets into the sequence.

ABCBCDEFGH

3. INVERSION- THE PART OF THE CHROMOSOME GETS DELETED AND GETS PLACED IN AN INVERTED DIRECTION.

ABCFEDGH

4. TRANSLOCATION- When a segment of the gene gets removed and attaches at some other place.

ABCGHDEF