non-mendelian genetics Flashcards
what does the breaking down of alcohol require?
two enzymes: adh and aldh
what is incomplete dominance?
it occurs when the phenotype of a heterozygous appears as a mix of the dominant and recessive type
can everyone make adh enzymes?
yes
can everyone make aldh enzymes?
no
is the ability to make aldh dominant or recessive?
dominant
what happens to recessive people when they drink alcohol?
they can’t break it down and flush red as acetaldehyde builds up
what happens to Aa people when they drink alcohol?
they can produce some enzymes, but not enough to fully deal with acetaldehyde (semi-tolerant)
what dud mendel’s work suggest?
that only two alleles existed for each gene
what is an exmaple of multiple alleles?
abo blood groups
what are the a and b bllod types?
codominant and can exist together as blood type ab
what’s the phenotype of someone with ii
type O
what is pleiotropy?
when a single gene affects multiple phenotypes
why do many genetic disorders (ex. a single amino acid change) produce multiple harmful symptoms?
because of pleiotropy
give an example of pleiotropy
people with dry earwax tend to have less body odor
give another example of pleiotropy
albinism
give an example of a dominant allele
freckles
what genotypes are possible for people with freckles?
FF and Ff
What do lethal alleles cause?
death in any organism that carries them
are lethal alleles dominant or recessive
can be both
what do recessive lethal alleles kill?
homozygote
what do dominant lethal alleles kill?
homozygote or heterozygote
what is dwarfism caused by?
a dominant allele
what does the huntington’s disease cause?
death of brain cells
what is huntington’s disease caused by?
a dominant lethal allele
what does huntington’s disease eventually do?
kills those that are heterozygous
what are sex-linked traits?
traits passed on the sex chromosome
what are the sex chromosomes?
x and y
what is the male genotype
XY
what is the female genotype?
XX
where are x-linked traits carried on?
the x chromosome
why do sex-linked traits affect more men than women?
males only have a single copy of the x chromosome, while women have two
what does the law of independent assortment say?
alleles are passed on independently of one another
X^A
dominant
X^a
recessive
is the law of independent assortment always true?
no because some genes are linked
where do linked traits exist?
on the same chromosome, so they dont get independently assorted
where are the linked trait genes on the chromosome?
close, so even if crossing over occurs, the genes cross over together
what do fewer recombinant organisms equal to?
the closer together the genes are on the chromosome
what are recombinant genes
combinations of genes not found in the parents
what does the recombination frequency of the genes help determine?
where they lie on chromosomes
what is the maximum recombination frequency?
50%
what does a high rate of recombination mean?
the two traist are far away on a chromosome
