Gene and Chromosome Dynamics Flashcards
What is a karyotype?
an individual’s full set of chromosomes
What is a chromosome made up of?
2 sister chromatids joined by a centromere
What is a gene loci?
the location for a specific gene on a specific type of chromosome
When does DNA within chromosomes become visible?
when they become compact, sausage-shaped structures in preparation for cell division
What is recombination?
the rearrangement of DNA sequences by the breakage and re-joining of chromosomes or chromosome segments
When does recombination occur?
during the crossing over event in meiosis (prophase I)
What is translocation?
where a chromosome breaks and either the whole thing or a portion of it reattaches to a different chromosome to produce non-homologous chromosomes
What is the detection of chromosomal translocations important for?
the diagnosis of certain genetic diseases and disorders
What is ataxia?
the progressive loss in motor skills that can arise due to translocation
When does chronic myelogenous leukaemia arise?
when the bone marrow produces too many white blood cells caused by a translocation between chromosomes 9 and 22
What do insertion mutations involve?
the addition of one or more nucleotides into a segment of DNA
What are the 2 types of chromosomal insertion?
- interchromosomal - when a segment of one chromosome is translocated and inserted into an interstitial region of another non-homologous chromosome
- intrachromosomal - when a segment of one chromosome is translocated and inserted into an a different region of the same chromosome
Why do deletion mutations shorten chromosomes and what can it lead to?
part of a DNA molecule not being copied during regulation and can lead to genetic diseases e.g. Cri du Chat syndrome
What are duplication mutations?
when one or more copies of a DNA segment is produced
What is chromosome segregation?
the partitioning of genetic material into 2 identical daughter cells driven by the mitotic spindle
