Chromosome and Karyotype Rearrangements Flashcards
What are the different types of changes that can be made to chromosomes?
Number: aneuploidy and polyploidy
Organization: deletions, duplications, breaks, inversions, translocations
What is aneuploidy?
2n+/2n-
Mistakes in meiosis during zygotic/embryonic development
What are autosomal monosomy?
rare in animal kingdom; unmasks lethal alleles
What are autosomal trisomies?
phenotypic effects similar to monosomies
- Small chromosomes can be viable
- Large chromosomes are lethal
What is trisomy 21?
Down Syndrome: extra chromosome
What is Trisomy 13?
Patau Syndrome
What is Trisomy 18?
Edwards Syndrome
What is polyploidy?
more than 2n chromosome sets
What are the different types of polyploidy?
Germline events- rare
1. Tetraploids
2. Triploids
Somatic Genome duplication- common
What are the Type I changes of structural chromosome aberrations?
Deletions, duplications, inversions, translocations
What are deletions?
loss of any genetic material (single locus or larger segments)
What are the different types of deletions?
terminal: 1 break
intercalary: 2 breaks
What are duplications?
any part of genetic material is present more than once
What is the mechanism of deletions?
chromosomal breaks
What is the mechanism of duplications?
unequal crossing over or DNA replication errors