Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

47 Cards in this Set

  • Front
  • Back
epistasis 1
interactions of different genes in which an allele of one gene masks the expression of alleles of another gene.
constant expressivity
genotype always produces expected phenotype
dihybrid phenotypic ratio 2

Any deviation from this means that the phenotype is the product of the interaction of 2 or more genes.
sex limited traits
genes that are on autosomes affect a particular character that appears in one sex but not the other
crossover frequency
frequency of physical exchanges between chromosomes in meiosis for the region between the genes

the farther apart 2 genes are, the greater the crossover frequency
variable expressivity
genotype doesn't always produce expected phenotype
recombination frequency
the frequency of recombination of genetic markers in a cross as determined by analyzing the phenotypes of the progeny.
the degree to which a penetrant gene or genotype is phenotypically expressed in an individual.

depends on genotype and environment and may be constant or variable
Gene interaction 1
progeny that has a phenotype that no parent has
progeny showing parental combos of the alleles.
hypostatic 1
the gene that is being masked in epistasis
genetic recombination
the process by which recombinants are produced.
multiple alleles 2
in a population, a gene has many forms of alleles.

A diploid individual only has 2 forms, one on each chromosome.
progeny showing non parental combinations of alleles.
recessive epistasis 2
a/a B/- and a/a b/b individuals have the same phenotype

the phenotypic ratio is 9:3:4.

genetic analysis
dissection of the structure and function of genetic material.

progeny from crosses between parents with different genetic characteritics are analysed to see frequency with which different alleles are associated into different combinations.
complete dominance 3
one allele is dominant to another

the phenotype of the heterozygote is the same as homozygous dominant.

The same phenotype results wether the dominant allele is heterozygous or homozygous.
genes on the same chromosome

don't always assort independently
each homologue has a wild type allele and a recessive mutant allele

also called trans configuration
independent assortment
assumes genes are on different chromosomes or far away from each other on the same chromosome
complete resessiveness: when is it expressed? 2
the recessive allele is only phenotypically expressed when the organism is homozygous.

The recessive allele has no effect on the phenotypic outcome of the heterozygote.
examples of diseased genes being sex influenced:
men: cleft palate, clubfoot, gout.

women: arthritis, lupus, osteroporosis, thyroid disorders
2 wild type alleles are on one homologue, and the 2 recessive mutant allels are on the other homologue

also called cis conformation
nature vs. nurture
social environments affects phenotype.

ex: alcoholism; the genes don't actually make the person an alcoholic, social situations contribute.
incomplete dominance 2
when one allele is not completely dominant to another allele. The heterozygote's phenotype is in between the two alleles.

It is a mix of the two alleles EX: red and white flowers produce pink.

the place on a homologous pair of chromosomes where the physical exchange is happening.

the site of crossing over
duplicate resessive epistasis 3
an interaction of two genes to give rise to a specific product.

ex. pea flowers. If the flower is homozygous recessive at either gene loci, it will be white.

Either gene pair produces the same phenotype. THe homozygous recessive alleles mask the dominant alleles of the other gene.
autosomal recessive disorder

can't handle phenylaliine in your diet.

severe mental retardation will occure if there is.
a phenomenon that occurs when a developing organism is exposed to certain drugs, viruses or chemicals at critical points in development
crossing over
the process of reciprocal exchange of chromatid segments

involves breakage of two chromatids and rejoining

leads to genetic recombination between linked genes

takes place during prophase I of meiosis
how age affects phenotypic expression:
not understood how

some phenotypes come out at certain ages

ex:pattern baldness 20-30 yrs
duchenne muscular dystrphy 2-5 yrs
pattern baldness
gene is dominant in males, and recessive in females.

expression of gene influenced by testosterone.

also shows variable expressivity.
Temperature sensitivity:
some alleles work at different temps.

ex: himilayan rabbits fur color is dependant on temp.

used in the lab to manipulate genes.
chemical environmental disruption:
chemicals can effect the phenotype exibited by a genotype.

Phenylketonuria in humans
sex influenced traits
often on autosomes

may appear in both sexes, but frequency or phenotype is different between sexes
codominance 1 + example
offspring show phenotype of both parents.

ex: AB blood groups you get a copy of the same allele from each parent, but they differ.
examples of phenocopy
rubella infection in mom in first 12 weeks

thalidomide for morning sickness caused babies with no arms or legs

not gentic defects, just look as though they are.
lethal allele
causes death of an organism because of an essential gene.
incomplete penetrance
less than 100% show phenotypes expected.
essential genes
when mutated these genes cause death.
What ratio is produced by interbreeding of two incomplete dominant individuals? EX: two grey chickens
linked genes
genes that don't assort independently.

belong to a linkage group
hla antigens
these antigens are codominant, so you will express the tissue typing antigens of both your mother and father.

in the case of a transplant you are most compatible with a sibling.
complete penetrance
when 100% of individuals are homozygous recessive show that phenotype
100% who are homozygous dominant show that phenotype

and 100% that are heterozygous are alike
dominant lethal allele
both homozygotes and heterozygotes for that allele will show the lethal phenotype
degree to which a gene expresses itself in a population.

dependant on genotype and the environment.
recessive lethal allele
only homozygotes for that allele will have the lethal phenotype.