Chapter 7: Genetic Linkage Flashcards
Chromosomes are made up of
DNA
certain units of DNA that influence an organism’s traits are known as …
genes
one chromosome has _________ of ______ on it
thousands, genes
every cell carries a copy of all your chromosomes (except _________)
gametes
genes are inherited via chromosomes passed down through….
meiosis
Mendel’s Laws of Segregation & Independent Assortment establish…..
a baseline for inheritance
Synteny
when 2+ genes are located on the same chromosome
the phenomenon in which genes that are close together on the same chromosome tend to be transmitted as a unit
Genetic linkage
What does genetic linkage violate?
Medel’s law of segregation
chromosomes can be referred to as a ________ group
of linkage groups = # of chromosome types
linkage
# of linkage groups = # of chromosome types
F1 generation was ___________
heterozygous
F2 generation showed a ratio of 15.6:1:1.4:4.5 but it should have a ratio of ________
9:3:3:1
F2 generation does not __________________
follow normal inheritance pattern
Crossing over occurs during meiosis one to
create genetic variation
Recombinant
combinations of alleles or traits that are not found in the true-breeding paternal generation
nonrecombinant
gamete or offspring in which no crossing over has occurred
Genetic recombination occurs in what two ways?
- crossing over
- Independent assortment
Genetic recombination can occur in __ chromosome but not __ due to ___________________
X, Y, size and function of the chromosome
The likelihood of crossing over is dependent on
distance between two genes on a chromosome
how do we know if the resulting genetic variation is due to crossing over or independent assortment?
Chi-square analysis
Step 1 of Chi-square analysis
propose a hypothesis
step 2 of Chi-square analysis
determine your “expected” values
Step 3 of Chi-square analysis
compare observed results to the expected results.
Null Hypothesis
assumes there is no real diff between the observed and expected values
Step 4 of Chi-square analysis
calculate for chi-squared
Chi-square analysis results determine
the distance
*the lower the number the closer together they are
genetic mapping method used to determine the _____ _____ and ________ __ ________ of genes that are ______ to each other on the same chromosome
linear order, distance of separation, linked
why is genetic mapping useful?
in praactice
- diseases
- breeding
- evolution and history
genetic mapping relies on
distance
genes close together =
less likely to experience crossing over
genes far apart =
more likely to experience crossing over
if many recombinant offspring are produced the genes must be
farther apart
if few recombinant offspring are produced the genes must be
close together
why are there nonrecombinants
crossing over occurs in 10% of meiosis
Its rare
the two recombinant types of offspring can only be produced if crossing over occurred _______ the two linked genes.
between
F2 recombinant offspring carry a chromosome that
underwent crossing over
Map distance =
(# of recombinant offspring/ total # of offspring) X100
The closer to _____% of offspring that are recombinant, the _____ accurate this mapping technique is.
50, less
Mitotic recombination
can happen occasionally
