Genetics and Health Week 2

Question 1

Define Single Nucleotide Polymorphisms

Answer 1

Position in a genome where there is a difference in nucleotide

Question 2

Define Copy Number Variants

Answer 2

Large chunks of DNA that are deleted, copied, flipped or otherwise rearranged in combinations that are unique for individuals

Question 3

Define each of the main causes of chromosome abnormalities
1) Anaphase lag
2) Chromosome missegregation (Non-Disjunction)
3) Meiotic mitotic failure
4) Dispermy
5) Incorrect DNA Repair
(Pericentric and Paracentric Inversion)
(Insertional Translocation and Reciprocal Translocation)

Answer 3

1) Anaphase Lag: one chromosome fails to migrate in the division of cells, will be degraded, resulting one partner cell lacking a chromosome

2) Chromosome missegregation (Non-Disjunction): 
Meiosis 1 (failure of homologous chromosomes separating, resulting in 3 different copies of the chromosome) 
Meiosis 2 (Failure of sister chromatids, resulting in 3 similar copies of the chromosome) 

3) Duplication of chromosomes, but no cytokinesis
4) 1 egg and 2 sperm
5) Inversions, Translocations, deletions, duplications

Pericentric (includes centromere) and Paracentric

Insertional Translocation: one segment of a chromosome is inserted onto another chromosome

Reciprocal Translocation: two segments from each chromosome are switched with each other

Question 4

What is the difference between Aneuploidy and Polyploidy ?

Answer 4

Aneuploidy: addition or loss of chromosomes

Polyploidy: addition of a set of chromosome

Question 5

Explain the causes of Barr Bodies

Answer 5

In females, one of the X chromosome gets inactivated