Ms 59-65 & probability, blood, and pedigree labs Flashcards
what is a gene?
stretch of DNA encoding a protein product
what are alleles?
different versions of a gene
diploid cells?
2 alleles from each gene (pat. mat.)
where are alleles located?
the same loci on homologues (pat. mat.)
how are new alleles produced?
mutations
heterozygous?
two copies of different alleles (carrier/ hybrid)
homozygous?
two copies of same allele
genotypic and phenotypic ratio of a hybrid cross?
2: 1:1 genotypic
3: 1 phenotypic
who is the “Father of Genetics”?
Gregor Mendel
what did Mendel not know about?
genes
meiosis
DNA
what is single-gene inheritance?
traits controlled by the expression of one gene
All traits Mendel studied were what?
complete dominance
Mendel used what kind of crosses?
genetic crosses with true-breeding parents
what is the law of segregation?
alleles from each gene are segregated during meiosis
what are the generation names from top to bottom
P generation (True-breeding) F1 generation (hybrids) F2 generation (mix of hybrid and true-breeding)
what happens if the wrong blood type is given to a person?
the anti antigen bonds to the blood, clumping and causing clots
what is mother-fetus incompatibility?
if the fetus is Rh+ and mother is Rh- then mom’s immune system may attack baby’s blood
what is a dihybrid cross?
2 true breeding plants for 2 traits
has 4 alleles in the genotype, making a 16 square Punnet Square
what ratio is typical of a dihybrid cross with non linked genes?
9:3:3:1
what is the law of independent assortment?
The inheritance of one trait is independent of the inheritance of another trait
Who did the fruit fly experiment?
Thomas Hunt Morgan
what did Morgan’s results conclude?
opposed IA
discovered genetic linkage
studied wing length and body color
what do you call phenotypes controlled by one trait?
monogenic (Mendelian traits)
what do you call phenotypes controlled by multiple traits?
polygenic
monogenic follow what?
simple patterns
polygenic follow what?
complex patterns
another word for incomplete dominance?
blending
examples of incomplete dominate AKA blending?
snapdragons, palomino horses
what is co-dominance?
some of both traits
examples of co-dominance?
blood(AB), sickle-cell anemia
what are Environmental Effects?
the rate/amount a gene is expressed is affected by the environment
example of Environmental Effects?
alligators ( low temp.=female, high temp.=male)
Siamese Cat Coat Color (tyrosinase pigment levels higher at lower temp.)
what are Pleiotropic genes?
when 1 gene influences multiple traits
example of Pleiotropic genes?
albinism
what happens if the tyrosinase gene in albinos is mutated?
can lead to hypo pigmentation and eye problems
what is there a balance between when determine pigment levels of people?
a balance between folate and vitamin
what are sex-linked traits?
traits coded for by genes on sex chromosomes
examples of sex-linked disease?
hemophilia
which disorders are both sexes equally likely to inherit?
autosomal disorders(non sex-linked)
what do you call alterations in chromosomal structure?
chromosomal aberrations
what other way can you get genetic disorders besides inheritance?
chromosomal aberrations
what is Aneuploidy?
mistake made during anaphase of meiosis resulting in too many or too few chromosomes in a gamete
what does Aneuploidy usually lead to?
death
examples of Aneuploidy?
trisomy 21 (Down Syndrome) Klinefelter's syndrome (XXY, reduced fertility, female characteristics)
four kinds of Chromosomal Aberrations?
Deletion (segment with genes lost–> XY female)
Duplication (locus “stutter”, genes duplicated–> breast cancer)
Inversion (broken segment reattaches in wrong orientation———->infertility)
Translocation (broken segment reattaches to wrong chromosome—> XX male)
what cells are not involved in reproduction?
somatic cells
what cells undergo meiosis to produce gametes?
germ line cells
what alleles arise due to mutations?
disease alleles
why is being homozygous dominant rare for a disease?
usually results in an embryonic lethal
what are Genetic disorders?
set of symptoms caused by inherited alleles
Autosomal recessive?
males+females ~equally affected
can skip generations
unaffected parents can have affected offspring
2 affected parents=all offspring affected
Autosomal dominant?
males+females ~equally affected
can not skip generations
affected offspring must have at least 1 affected parent
no carriers
usually not homozygous dominant= embryonic lethal
X-linked recessive?
more common in males
affected male x carrier female = 50% daughters affected
X-linked dominant?
affected male= 100% of daughters affected
affected female= 50% of offspring affected
how to determine %probability of trait?
decimal percentage of each parent multiplied
