one gene affects another gene at a different locus
Solid evidence associating a specific gene with a specific chromosome was missing, who found the missing evidence?
Thomas Hunt Morgan
What did Morgan's experiments conclude?
Fly's eye color is linked to its sex
Results from Morgan's experiment provided that a specific ____ is carried on a specific ________
gene, chromosome
What do genes located on a sex chromosome exhibit?
unique inheritance pattern
What are "linked genes"?
genes located on the same chromosome that tend to be inherited together in genetic crosses
What mechanism breaks the linkage between genes on the same chromosome? (list 3)
crossing over
prophase I of meiosis
percentage of recombinant offspring, the recombinant frequency, is related to the distance between linked genes
What is recombination frequency?
the percent of recombinant offspring
In mammals, the sex of an offspring depends on whether:
the sperm cell contains an X chromosome or a Y chromosome
Since females have 2 X chromosomes, each gene on the X could be expressed at twice the level as in males. How are genes on the X chromosome expressed at equal levels in males and females?
by shutting off one homolog (in females)
What is a barr body?
one X chromosome per cell condenses into a compact object
occurs during female develpment
Where and why is the condensed barr body chromosome reactivated?
in ovarian cells to produce ova
What is the philadelphia chromosome?
a chromosome abnormality that causes chronic myelogenous leukemia
What is deletion? (alteration of chromosome)
when a chromosomal segment is removed
What is duplication? (alteration of chromosome)
when a segment repeats itself
What is inversion? (alteration of chromosome)
when a segment within a chromosome reverses
What is translocation? (alteration of chromosome)
when a segment is moved from one chromosome to a non-homologous chromosome
What is one example of an exception to chromosome theory of inheritance? (provide definition of example)
genomic imprinting- epigenetic phenomenon that occurs during the formation of the gametes and results in the silencing of one allele of certain cells