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Ch 10-12 Genetics

Ch 10-12

Question	Answer
Hermann Henking	1891, observed the X chromosome and called it the X body
Clarence McClung	Observed the X chromosome in grasshoppers and called it the accessory chromosome. The name later changed to X chromosome.
Nettie Stevens and Edmund Wilson	1905, they described the XX-XO system in grasshoppers. XX = female XO = male
homogametic	the sex that produces gametes that are alike with regard to sex chromosomes.
heterogametic	the sex that produces two types of gametes with regard to sex chromosomes.
Hermann Henking	1891, observed the X chromosome and called it the X body
Clarence McClung	Observed the X chromosome in grasshoppers and called it the accessory chromosome. The name later changed to X chromosome.
Nettie Stevens and Edmund Wilson	1905, they described the XX-XO system in grasshoppers. XX = female XO = male
homogametic	the sex that produces gametes that are alike with regard to sex chromosomes.
heterogametic	the sex that produces two types of gametes with regard to sex chromosomes.
pseudoautosomal region	X and Y chrom. are not homologous, but are able to pair and segregate into diff. cells in Mei. They can pair b/c they are homologous at small regions called pseudoautosomal regions.
sex determining region Y (SRY)	on Y chromosome only.
TDF	testes determining factor
Wolfian Duct	Develops with the presence of testosterone (male).
Mullerian Duct	no testosterone, so mullerian duct develops (female)
mullerian inhibiting factor/substance (MIF/MIS)	gene on Y chromosome causes gonads to secrete MIF, which leads to the degeneration of female reproductive ducts.
Structures that develop from Wolfian Duct	prostate, vas deferens, penis and testes
Structures that develop from Mullerian Duct	uterine tube, ovary, uterus, and vagina
These structures can sometimes form compartments during development during fusing of Mullerian ducts.	Uterus and vagina (rarely)
Sex determination is determined by	testosterone. no testosterone, default female.
dihydrotestosterone (DHT)	is an androgen, synthesized primarily in the prostate gland, testes, hair follicles, and adrenal glands by the enzyme 5α-reductase.is responsible for the formation of secondary sex characteristics in men.
sex-reductase (5 alpha)	an enzyme that reduces testosterone to DHT (very potent)
haplodiploidy	instead of sex chromosomes, sex is determined by haploid (male) and diploid (female)
dosage compensation	equalization in males/fem of the amt of protein produced by X-linked genes. In placental mamm, dosage comp is accomplished by random inact. of 1 X chrom in cells of females.
Thomas Hunt Morgan	first studied sex linked inheritance of Drosophila melanogaster. concluded that white eyes was inherited through X-linked inheritance.
hemizygous	possession of a single allele at a locus. Males of organisms XX-XY sex determination are hemizygous for X-linked loci, bc cells possess a single X chrom.
completely normal	no signs of disease and not a carrier
appears normal	could be a carrier
hemophilia	mutant F8 & F9 genes, code for clotting factors VIII & IX.
penetrance	% of individuals w/a particular genotype that express the expected phenotype.
expressivity	degree to which a character is expressed.
sex influenced traits	same gene works differently depending on sex. determined by autosomal genes, inherited according to Mendel's principle. Ex: male pattern baldness, autosomal allele dom. in males and recessive in females.
sex limited traits	may be X linked or autosomal. Extreme form of sex-influenced inheritance w/ zero penetrance in one sex. ex: changes during puberty and cock feathering(autosomal recessive trait sex-limited to males)
precocious puberty	male-lim. males with this autosomal dom. allele undergo pub. at a early age, usually before 4 yrs. receptor for LH is mutated and on even in the absence of LH. same genes have no effect on fem.
LH	Luteinizing hormone. stimulates the production of testosterone.
cytoplamsic inheritance	inheritance of characteristics encoded by genes found in cytoplasm. cytoplasm is usually contributed by only one parent so these characteristics are inherited from only one parent.
LHON	result from mutations in mtDNA. experience rapid loss of vision from death of optic nerve cells, usually in early adulthood.
genetic maternal effect	(not cytoplasmic inher) genotype of mother determines the phenotype of children.
genomic imprinting	the differential expression of genetic material depending on whether it is inherited from the male or female parent. ex) expression of Igf2, only expressed when transmitted by dad.
epigenetics	phenomena due to alterations to DNA that don't include changes in the base seq. affect the way dna seq is expressed. such alterations are stable and heritable.
genomic imprinting	whether the gene passes thru the egg or sperm determines how much methylation takes place. methylation remains on dna thru mitosis and ult. determines if gene is expressed in offspring.
epigenetic marks	reversible changes to DNA that influence the expression of traits. may be responsible for cancer.
SCID	(bubble boy). X-linked mutant "interleukin 2 receptor gamma" (IL2RD). No bubble girls b/c boys are isolated. also, 1 normal X comes from mom which is makes enough normal to have normal immune system.
Possible solution for SCID	Bone marrow transplant to replace faulty immune cells.
Duchenne Muscular Dystrophy (DMD)	mutation in dystrophon gene. males have short lifespan.
DMD in females	produces a protein that stays in cell (heterozygous carrier). Some cells can have normal X and some have mutant X activated. Women will have active patches of muscle and abnormal patches. Random areas are affected.
X-linked diseases	hemophilia, SCID, DMD and colorblindness. Females can be homo or heterozygous. Males are hemizygous.
male pattern baldness	a sex influenced trait. autosomal allele dominant in males and recessive in females.
If a male is hetero/homozygous for male pattern baldness...	the male will start balding later/earlier in life.
If a woman is heterozygous for baldness...	female will not bald, gene behaves like recessive allele.
If a woman is homozygous for baldness...	She will bald later in life.
cock-feathering	autosomal recessive trait sex-linked to males. hh = bald male Hh/hh= hen feathering in males. hh/Hh/HH = hen feathering in females.
dominant lethal alleles	tend to disappear b/c carriers will die before reproductive age. ex: Y alleles for coat color in mice is recessive for fatality, need 2 copies . exception: huntingtons disease.
lethal alleles	tend to be recessive
multiple alleles (allelic series)	more than 2 alleles in population, but only 2 in an individual. inherince sim. to when 2 alleles are present, but greater variety. ex: ABO blood group system.
antigens	molecules recognized by the immune system.
Universal blood acceptor	AB
Universal donor	Type O
Type A blood has type__antigen and produces type__antibody and will attack type__antibodies.	A, B, A
Cross and Type Match Test	mix blood from donor and acceptor to see if clumping occurs (bad)
Type AB has type__antigen and produces__antibody and will attack__antibody	AB, none, none
Rh (Rhesus) factor	Dominant allele, D. Has 3 genotypes and 2 phenotypes. DD/Dd = + and dd = -.

dominant lethal alleles	tend to disappear b/c carriers will die before reproductive age. ex: Y alleles for coat color in mice is recessive for fatality, need 2 copies . exception: huntingtons disease.
lethal alleles	tend to be recessive
multiple alleles (allelic series)	more than 2 alleles in population, but only 2 in an individual. inherince sim. to when 2 alleles are present, but greater variety. ex: ABO blood group system.
antigens	molecules recognized by the immune system.
Universal blood acceptor	AB
Universal donor	Type O
Type A blood has type__antigen and produces type__antibody and will attack type__antibodies.	A, B, A
Cross and Type Match Test	mix blood from donor and acceptor to see if clumping occurs (bad)
Type AB has type__antigen and produces__antibody and will attack__antibody	AB, none, none
Rh (Rhesus) factor	Dominant allele, D. Has 3 genotypes and 2 phenotypes. DD/Dd = + and dd = -.
Rhogam	an antibody given to mother to destroy RBC that come from baby that may enter mothers blood stream so she doesn't become sensitized.
IgM	Larger and doesn't cross placenta.
IgG	Smaller and may cross the placenta.
bombay phenotype	recessive epistasis. supresses the expression of alleles at ABO locus. The ABO locus is hypostatic to the recessive h allele. functions as O.
FUT1 (fuctosyl transferase)	The recessive allele h prevents synthesis of complete H substance-lacks fucose moeity so enzymes made by A and B alleles can't add appropriate sugars.
recessive epistasis	9:3:4 homozygous recessive allele for a gene masks the expression of another gene at a different loci. ex: labs and bombay phenotype.
dominant epistasis	12:3:1 The dominant allele at one locus masks the effect of alleles at another locus. ex: fruit color in summer squash.
duplicate recssive epistasis	9:7 both genes are epistatic to each other. ex: albinism in snails
cytoplasmic inheritance	DNA from sperm enters oocyte to form male pronucleus in fertilized egg, but all mitochondria are provided by oocyte. mito segregate randomly in cell div.
heteroplasmy	mix of mitochondria w/wild type and mutated genes.
homoplasmy	either all mtio w/wild type or all mutated genes
mitochondrial mutations usually affect only certain tissues...	that require high amts of ATP, require synthesis of sufficient quantities of functional mito proteins (coded for by mtDNA).
LHON (Leber's hereditary optic neuropathy)	degeneration of optic nerve accompanied by increasing blindness. Caused by missense mutation of mtDNA gene coding for a subunit of NADH-CoQ reductase
Ooplasmic transfer	mitochondria from a healthy woman are injected into the oocyte of women with mitochondrial disorder.
maternal effect	(not cytoplasmic inheritance) genotype of mother determines phenotype of progeny.
polygenic inheritance	many genes act together for 1 phenotype (skin color, ht, eye color). Continuous characteristic. Effect of alleles is additive or synergistic.
polygenic traits	also called "quantitative trait" or "quantitative characteristic" as many phenotypes are possible and any individuals phenotype must be described by quantitative measurement.
genomic imprinting	the differential expression of genes depending on whether the gene is inherited from the male or female parent.
Igf2	ex of maternal imprinting. maternal copy is silent. the protein, insulin like growth factor is expressed in fetus and placenta & promotes fetal growth by directing more maternal nutrients thru placenta.
H19	ex of paternal imprinting. allele derived from father is inactive.
Consequence of genomic imprinting	imprinted genes are expressed as if there was only one copy present in a cell even though there are 2. causes monoallelic inheritance. no change in DNA seq.
How does genomic imprinting occur?	The DNA regulatory regions of imprinted gene is methylated at specific cytosine in a sex specific manner during gamete formation.
epigenetic inheritance	a process that affects the expression of genes; often a process that brings about genetic alterations that can be reversed, such as the methylation of DNA.
3 reasons for Pedigree analysis in humans	controlled mating not possible, long generation time, small family size.
pedigree	pictorial representation of a family history, a family tree that outlines the inheritance of one or more characteristics.
analysis of pedigrees requires..	recognizing patters associate w/different modes of inheritance.
Wardenburg syndrome	autosomal dominant trait. deafness, fair skin, visual problems and a white forelock.
autosomal dominant trait appears in...	both sexes w/equal frequence and does not skip generations. unaffected person do not transmit the trait.
autosomal recessive trait appears in...	both sexes w/equal frequency and seems to skip generations. are more likely to appear among progeny of related parents.
X-linked recessive trait appears in...	more often in males. Not passed from father to son, but can pass to daughters.
X-linked dominant trait appears in...	both males and females. Affected male has an affected mother. does not skip generations. Affected female (hetero) pass the trait to about 1/2 their sons and 1/2 daugthers.
Y-linked traits	appear only in males. passed only from father to son.
amniocentesis	small amt of amniotic fluid is withdrawn from amniotic sac which contains fetal cells which are separated from amniotic fluid, cultured and tested. `
chorionic villi sampling (CVS)	a catheter is used to remove a small piece of chorion. cells of the chorion are used directly for genetic testing. very invasive, can harm fetus, or cause bleeding in placenta.
fetal cell sorting	fluorescence/magnetic anti-CD71 to fetal cells. a specific antigen is found only on fetal cells that bind to anti-CD71.
blood tests	alpha-fetoprotein is very high in fetuses with neural tube defects.
interchromosomal recombination	occurs btwn genes on different chromosomes (ind assortment). Due to random segregation of chromosomes in ana I of meiosis.
intrachromosomal recombination	occurs btwn genes located on same chromosomes. Due to crossoing over in pro I of meiosis.
complete linkage	leads to nonrecombinant gametes and nonrecombinant progeny.
crossing over between linked genes	leads to recombinant gamete and recombinant progeny. frequency depends on gene proximity.
With independent assortment, ___the progeny are recombinant and ___are not.	1/2, 1/2
If genes are completely linked (no crossing over)only _______progeny are produced.	nonrecombinant
You can never have more than ___% recombination.	50%
genetic maps are determined by...	calculating recombination frequencies.
linkage group	consists of genes located together, less than 50 m.u. apart on same chromosome.
In Cis/Trans	phenotype is the same, but rearrangement of genes at chromosomal level is different and affects how genes are passed on.
coefficient of coincidence	the ratio of observed double cross overs to expected dbl cross overs.

Created by: jriendea

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