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33 Cards in this Set
- Front
- Back
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Law of dominance
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when there are 2 alleles present for a trait, one of them will completely mask the effects of the other
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law of segregation
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two alleles from one parent separate when gametes are formed. a parent at random passes on one allele for each trait to their offspring. (see diagram)
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law of independent assortment
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genes for diff. traits are inherited independently of each other, meaning genes for the same trait do not necessarily separate together. This results in an assortment.
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crossover variety
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-genes on same chromosome are inherited differently
-when homologous chromosomes trade pieces w. each other cuasing genes that used to be linked to be separated |
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allele
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a form of a gene, codes for a particular trait. T or t are alleles for the trait of height.
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homozygous (dom. & rec.)
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2 alleles of the same kind for a trait:
-Homozygote dominant=TT -Homozygote recessive=tt |
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Heterozygous
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mixed alleles for a trait=Tt
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dominant
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it only takes on allele for it to show--it masks the recessive
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recessive
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must be the only allele type present in order to be seen
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genotype (&ratio)
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-what alleles are present; letters to represent the genes=TT or Tt or tt
-genotypic ratio=how many of each genotype=1TT:2Tt:1tt |
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phenotype (&ratio)
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-what it "looks" like; words to desribe the trait=tall or short
-phenotypic ratio=how many of each phenotype=3 tall: 1 short |
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polygenic
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many genes causing one trait ex: skin color (see diagram)
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pleitropy
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one gene causing MANY traits ex: Marfan's syndrome (see diagram)
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multifactorial (PKU, rabbit)
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-effected by more than the genes-like diet or environment can change effects
-ex: rabbit changes color b/c of temperature--it's not seasonal or built in -certain diseases (PKU) can be contained by putting them on certain diets and thus controlling their environment |
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testcross
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mating a known recessive with an unknown dominant
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linkage
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genes that are linked on teh same chromosome and are therefore inherited together (bond hair + blue eyes)
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linkage
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genes that are linked on teh same chromosome and are therefore inherited together (bond hair + blue eyes)
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mapping (units)
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figuring out the general placement of the genes and how far about they are (units are map units)
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human genome project
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mapping out the exact order of every base (ATGC) on every chromosome. Completed April 2003
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restriction enzymes (insulin)
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-act like molecular scissors and cut DNA at specific recognition sites--used to identify DNA like in fingerprinting.
-could make a DNA code for insulin that doesn't already exist |
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electrophoresis (uses + process)
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-a process used to separate DNA fragments by size, used in DNA fingerprinting; identifying proteins; identifying organisms or diseases
-gel poured into container w/ blocking plastic. when plastic removed, little holes left + DNA poured in (restriction enzymes cut DNA). shorter DNA swim faster through gel and that way can compare DNA by comparing how far DNA travel. |
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recombinant DNA/genetic engineering
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changing the DNA by combining DNA from diff. sources
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cloning
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-making exact copies of an entire organism (like Dolly) or using something like E. coli to make copies of a particular gene like for insulin
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nondisjunction
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-chromosomes fail to separate during Anaphase I or II-gametes end up w/ wrong number of chromosomes
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-Klinefelter's syndrome (nondisjunction)
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=XXY-male, sterile, mental problems
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-Jacob's syndrome (nondisjunction)
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=XYY, male, can have Klinefelter's children
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-Turner's syndrome= (nondisjunction)
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X__, female, webbed neck, sterile, mental problems
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-Superfemale (nondisjunction)
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=XXX-mental problems
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Downs Syndrome (nondisjunction)
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trisomy 21, mental problems, several physical issues
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Huntington's disease
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-dominant disease, shows up as adult
-effects motor function/speech, loss physical functions, wheelchair bound -prevalent in Amish pop. b/c isolate themselves and marry w/i themselves |
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Phenylketonuria (PKU)
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-recessive, can't make the enzyme to break down phenylalanine (amino acid)
-mental retardation prevented if tested at birth + put on diet |
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cystic fibrosis
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-recessive, most in Caucastions of Euro. descent (mutation that allowed ancesotrs to survive Black Plague b/c mucus clogged lungs)
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Tay-Sachs
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-recessive, mostly in Ashkenazic Jews + Dutch (b/c tend to want to marry w/i religion)
-lipid buildup in brain, death by 5 yrs. |
