Sept 24.chromosones, Genes, And Alleles Flashcards
How many chromosomes do humans have?
23
What is a chromosome?
A chromosome is a very large dna helix located in every cell.
What does XXY lead to? What dies X lead to?
Super tall in men. Turner syndrome in women
How many genes are in a single chromosones.
Possibly thousands
What is a gene?
A functional sequence of DNA that exists for generations, potentially long enough for natural selection to act on it
What is an allele?
One possible form of gene where there is more than one form. Brown eye alleles are dominant alleles
What is a mutation?
A process that leads to change in gene frequency spontaneous error in DNA replication that gets selected for its advantages.
ex. a resistant to malaria
What’s trait leads to a resistance to parasites?
Sickle shaped blood cells
What is genetic drift?
The change in gene frequency because genes passed from one parent to offspring through random selection.
What is the founder effect?
The founder effect is a special case of genetic drift in’s a small founder population example Afrikaners in South Africa and Huntington’s disease the dominant allele.
What is a bottleneck?
When population is drastically reduced for at least 1 generation, such that genetic diversity is lost.
Which continent has the most genetic diversity?
Afrika
When does evolution develop?
When there are changes in relative frequency of alleles over the course of succesive generations
What is modern synthesis?
Genes are heritable matter that Darwin’s theory relied on
What is artificial selection?
Dog breeding
