Chromosomal Variations and Translocations

The video discusses chromosome structure variations, including deletion, duplication, inversion, and translocation. Each type is explained with examples, such as the cry du chat syndrome for deletion and bar eye type in Drosophila for duplication. Inversions are detailed with paracentric and pericentric types, highlighting crossover effects. Translocations are described with reciprocal and Robertsonian types, including familial Down syndrome as an example.

What are the two main types of chromosomal variations?

• Duplications and inversions

• Mutations and deletions

• Increase or decrease in genetic material and rearrangement within chromosomes

• Translocations and inversions

What is a terminal deletion?

• Rearrangement of a chromosomal segment

• Loss of a chromosomal segment from the middle

• Duplication of a chromosomal segment

• Loss of a chromosomal segment from the end

Which syndrome is associated with deletion of the short arm of chromosome 5?

• Klinefelter syndrome

• Down syndrome

• Cri du Chat syndrome

• Turner syndrome

What is a tandem duplication?

• A gene is copied to a non-adjacent location

• A gene is copied adjacent to its original location

• A gene is inverted

• A gene is deleted

In Drosophila, what is the result of duplication of the 16A locus on the X chromosome?

• Increased number of eye facets

• Decreased number of eye facets

• No change in eye facets

• Change in body color

What is a paracentric inversion?

• Inversion that duplicates a segment

• Inversion that includes the centromere

• Inversion that deletes a segment

• Inversion that does not include the centromere

What happens to the dicentric bridge during meiosis?

• It duplicates

• It breaks randomly

• It inverts

• It remains intact

What is a reciprocal translocation?

• Inversion of a segment on one chromosome

• Duplication of a segment on one chromosome

• Loss of a segment from one chromosome

• Exchange of segments between two chromosomes without loss of genetic material

Which chromosomes are involved in Robertsonian translocation?

• Chromosomes 1 and 2

• Chromosomes 13, 14, 15, and 21

• Chromosomes 5 and 6

• Chromosomes 18 and 19

What is the result of a Robertsonian translocation involving chromosome 21?

• Cri du Chat syndrome

• Familial Down syndrome

• Klinefelter syndrome

• Turner syndrome