Chromosome mutations Flashcards
What kind of mutation is the notch wing in drosophila?
A deletion mutation
What is the cause of Cri Du Chat syndrome?
A deletion of the tip of chromosome 5 , children die young https://www.youtube.com/watch?v=TYQrzFABQHQ
How can deletions be useful to gene mapping?
In heterozygotes, can result in unexpected phenotypes presenting themselves
How have duplications been important mutations in the history of life?
The genome expanded likely by a series of duplications
What evidence is there that duplications may have driven expansion of genome?
Often find gene families, collections of similar genes on a chromosome that could have arisen from duplicating one gene
What are the two kinds of duplications?
Tandem and reverse
Which type of duplication is most frequent in non-functional DNA?
Reverse
Bar Eye mutation in drosophila is an example of what kind of mutation?
Tandem duplication, of a particular band of the X
What are some strange results from Bar Eyed drosophila crosses?
Some are born double-bar and some with normal eyes?
What is the explanation for aberrant crosses in bar-eyed drosophila?
Mispairing of tandem duplications
What is an important mechanism for increasing short repeats in the genome?
Mispairing of tandem duplications
What human disease is caused by mispairing of tandem duplications?
Huntington’s Disease
Are the number of repeats in the Huntington’s gene greater for men or women?
Men
What structure results from inversion mutations and can be seen under the microscope?
[Poop] Loop
What is the significance of the inversion loop on population genetics?
It suppresses crossing over, mechanical strain is too much and centromeres need to be conserved
What do inversion loops mean for humans?
Reduced fertility, about 1 in 50 people has a visible chromosome inversion
What is the significance of inversion for evolution?
Inverted genes cannot recombine with uninverted genes, sometimes whole complexes inverted and thus stay together
What is the main fertility problem with translocations?
Unbalanced translocations are severely damaging
How have translocation mutations been used in insect control?
Sending out millions of insects with translocations, causes half of all heterozygous offspring to die (unbalanced translocations); used for tsetse flies in africa
How has translocation been useful in gene mapping?
XX males with part of Y translocated onto the X, allowed for locating crucial sex-determining part of Y gene
Explain Position Effect Variegation
The position of an allele affects its expression, and alleles that change their position can change expression, important in cancer
What trait is used to explain PEV?
White-eye in drosophila, shifting to chromosome 4 and losing part of its recessiveness
Is cancer a genetic disease of somatic or germ cells?
Mostly somatic, but the distinction is fairly ambiguous; involves many mutations and not one genetic disease
What cancer is famously caused by a translocation mutation?
Burkitt’s Lymphoma
