BSCI222/GENETICS, DR. KOCHER: Exam 1
BSCI222/GENETICS, DR. KOCHER: Exam 1 BSCI222
Popular in Genetics
Popular in Biological Sciences
This 11 page Study Guide was uploaded by HannahJ on Saturday September 26, 2015. The Study Guide belongs to BSCI222 at University of Maryland taught by in Fall 2015. Since its upload, it has received 381 views. For similar materials see Genetics in Biological Sciences at University of Maryland.
Reviews for BSCI222/GENETICS, DR. KOCHER: Exam 1
I'm really struggling in class and this study guide was freaking crucial. Really needed help, and Hannah delivered. Shoutout Hannah, I won't forget!
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/26/15
Chapter 1 all organisms use genetic systems that are very similar genome complete set of genetic instructions encoded in DNA or RNA all genetic instructions in same format copydecoding processes are similar evolution is a 2 step process 0 inherited differences occur randomly o proportions change one is better than the other 0 transmission genetics heredity and passing of traits o chromosomes heredity genes on chromosomes gene mapping molecular genetics chemical natures of genes population genetics genetic composition of groups of the same species model genetic organisms are good for analysis fruit fly yeast mouse nematode pangenesis particles called gemmules carry information from different parts of the body to reproductive organs which are then passed to embryo at conception wrong 0 inheritance of acquired characteristics acquired characteristics can become hereditary wrong 0 preformationism homunculus fully formed mini adult is found in egg or sperm and grows over development blending inheritance blend of parental traits can t unblend later cell theory 0 Schleiden and Schwann 0 all life made of cells 0 cells come from preexisting cells 0 fundamental structure of living organisms o germplasm theory cells in reproductive organs have complete set of genetic info and passed to egg and sperm prokaryote no nuclear membrane no membrane bound organelles eukaryotic complex nucleus membrane bound organelles gene unit of information that encodes a genetic characteristic allele form of a gene genotype genetic information phenotype how the gene is expressedtrait nucleic acids made of nucleotides phosphate sugar base DNA bases TAGC thymine adenine guanine cytosine 0 RNA has uracil not thymine DNA has two complementary strands chromosomes hold genetic information mitosis somatic cells meiosis gametes Chapter 2 0 Walter Sutton 18771916 chromosomal theory of inheritance o metacentric centromere in the center 0 submetacentric centromere moves towards one end spindle mitosis 0 00000000 0 stages 00000 O O O O O 0 stages OOOOO 2A of Chapter 3 o Gregor O O O acrocentric centromere moves closer to tip telocentric centromere on very tip karyotyping by size and centromere location picture of all metaphase chromosomes telomere very ends of chromosome centromere holds sister chromatids together where kinetochores form to connect to fibers simple somatic cell division results in 2 daughter cells stays in G1 for most of life undergoes growth GO is nondividing stage G1S is checkpoint once here it has to divide 8 DNA duplicates GZ prepares for mitosis GZM checkpoint now can divide mitosis and cytokinesis and then start over interphase nuclear membrane disappears DNA is relaxed prophase DNA condenses spindle fibers form prometaphase nuclear membrane is gone spindle fibers and chromatids attach metaphase chromosomes line up on metaphase plate anaphase spindle fibers shorten one sister chromatid pulled to each side telophase at very end nuclear membrane reforms meiosis reductional division reduces number of chromosomes passed to gametes must start with correct number of chromosomes start with homologous chromatids separating then chromosomes separate of prophase 1 leptotene condense zygotene chromosomes pair together pachytene synaptonemal complex form align perfectly recombination occurs diplotene held together by chiasmata synaptonemal complex leaves diakinesis nuclear membrane disappears and spindle fibers form chromosomes possible gamete combinations Mendel true breeding with 7 traits pea color pea shape pea coat color pod color pod shape flower position stem length easy to control conclusion traits do not blend one appears in F1 but both passed to F2 I dominance I each has 2 alleles that separate when gametes form Mendel s First Law of Segregation 0 each individual has 2 alleles that form a trait one from mom one from dad 0 two alleles separate when gametes form 0 alleles separate in equal proportions probability rules 0 multiply when AND is used I prob of getting R and R I independent events 0 add when OR is used I prob of getting RR or rr I mutually exclusive conditional probability 0 additional information that modifies 0 ex TT and Tt what is the probability a tall plant is Tt I getTT12Tttt I have to eliminate tt so answer is 23 learn Pascal s triangle for problems like 0 prob of getting 5 girls one boy p qquot6 ChiSquared test Xquot2 OE2E degrees of freedom categories 1 p 05 if smaller than can t reject null hypothesis I CAN NOT ACCEPT HYPOTHESIS o if bigger than can reject null hypothesis dihybrid cross 9331 ratio Law of Independent Assortment 0 genes encoding different characteristics segregate independently of each other when gametes are formed 0 exception if really close together on chromosomelinkage Study Punnett Squares Branch Diagrams locus specific place on a chromosome where gene allele is found monohybrid cross parents only differ in one characteristic reciprocal cross cross where the phenotypes of male and female are reversed back cross cross between an F1 individual and one of the parental genotypes testcross one individual of unknown genotype is crossed with homozygous recessive tells genotype of first wildtype common allele for characters in animals 0000 Chapter 4 sex sexual phenotype male or female females usually produce larger gametes many ways to have sexdetermination 0 some have genes that don t match phenotype still go by phenotype haplodiploid system 0 male inseminates female female can chose whether or not to use sperm 0 males are haploid females are diploid o bees wasps ants social control 0 slipper limpet 0 first that settles is male turns to female through hormones environmental control 0 temperature I ex turtles and alligators how they lay their eggs hermaphrodites both male and female reproductive structures monoecious dioecious one organism has male or female reproductive structures chromosome theory of inheritance genes are located on chromosomes which serve as vehicle for segregation of gametes in meiosis XXXO 0 females are XX 0 males are XO 0 means no chromosome XXXY 0 females are XX 0 males are XY 0 HUMANS ZW ZZ o ZW is female heterogametic o 22 is male genic sex determination genotypes at more than 1 loci determine sex Thomas Morgan found sexlinked chromosomes 0 used Drosophila 0 short generation time easy to maintain high amount of eggs 0 looked at white eye mutant and red eye wild type I white was found to be sex linked when you cross in opposite directiondo a reciprocal cross you get different ratios sex determination in drosophila ratio of X autosomes nondisjunction o meiosis goes wrong split up wrong in metaphase 1 0 one gamete has either XX or XY and one is empty heterogametic sex gender that has two different kinds of gametes males in humans primary pseudoautosomal region tops of sex chromosomes act as autosome allow X and Y to match up SRY gene sex determining region on Y chromosome encodes transcription factor and stimulates genes that promote differentiation of testes androgeninsensitivity syndrome female appearance testes inside XY missing androgen receptor cells are insensitive to testosterone XY evolved from autosomes because 0 male determining gene acquired SRY sexually antagonistic selection genes that helped males near SRY gene reduction in recombination once a chunk is inverted it can t recombine again clonal inheritance accumulation of deleterious mutationsloss of genes I 22 of Y have repeating DNA with no active genes I palindromic sequences allow for recombination and stops too much decay implications of sexually dimorphic chromosome 0 chromosomes that are different 0 sex linked inheritance o dosage compensation and Xinactivation mosaicism color blindness sex linked 8 of males only 64 females Xinactivation 0 ratios of gene expression are uneven bc Y chromosome gradually lost genes 0 males evolved mechanism to get more expression out of one X chromosome 0 caused problems for females because X was then expressed more than autosomes females evolved to silence second X chromosome can t reactive within the individual 0 Xist coats X chromosome and makes it inactive barr body inactivated X females are functionally hemizygous at cellular level hypohidrotic ectodermal dysplasia o xlinked recessive o no sweat glands 0 usually impacts males women are phenotypic mosaics because of xinactivation Turner Syndrome XO girl underdeveloped secondary sex characteristics sterile short Klinefelter39s Syndrome XXY male at least one Y and multiple X reduced facial hair tall sterile PolyX XXX no distinct features 0000 Chapter 5 phenotypes are more complexcontinuous than simple dominant and recessive pairs productions of genes are enzymesproteins with biochemical functions additive when heterozygotes is exactly halfway between both homozygotes dominant when heterozygote and one homozygote show same phenotype partialincomplete dominance when heterozygote falls in between the two homozygotes not exactly half 0 heterozygote cross gives 121 ratio recessive same as recessive phenotype codominance phenotype of heterozygote shows phenotype of both homozygotes incomplete penetrance genotype does not always produce expected phenotype penetrance o of individuals who have a genotype and express the expected phenotype I ex 42 people have polydactylous allele 38 show it 3842 90 penetrance 0 amount above phenotypic threshold amount that show penetrance expressivity degree to which a trait is expressed 0 results from other genes and environmental factors temperature sensitivity 0 some enzymes work differently depending on temperature 0 rabbits body parts that don t stay warm turn black genes can be dominant in males but recessive in females maternal effect 0 phenotype of offspring is determined by the genotype of the mother 0 ex dextral vs sinistral shell MN blood groups show codominance o heterozygote show both M and N antigens multiple alleles more than 2 alleles present at one locus allelic series 0 genotype still consists of two alleles 0 ex ABO blood ABO blood 0 multiple alleles with different functionsenzymatic activity 0 3 alleles 6 genotypes I nn12 0 no antigens 00 anti A and B UNIVERSAL DONOR A A antigens AAAO anti B B B antigens BBBO anti A AB A and B antigens AB no antibodies UNIVERSAL ACCEPTOR o clump together if react lethal genes 0 yellow color in mice y x b 11 yb shows no dominance y x y 21 yb yy individuals die y is dominant with respect of coat color but recessive with respect to lethality if dominant homozygotes and heterozygotes for this allele die can t be transmitted to later generations unless expressed after reproduction gene interaction effects of genes at one locus depend on the presence of genes at another locus epistasis 0 one gene hides the effect of another gene at a different locus o epistatic gene does the masking o hypostatic gene the gene whose effect is masked 0 mutations in different genes complement each other s functions I ex waZ is white Wsz is white WwZz is purple 0 mutations are same locus can t complement each other 0000 0000 I ex w1w1 is white w2w2 is white w1w2 is white 0 9331 ratio of dihybrid cross may go to 97 ratio with epistatic interaction I 331 have some nonfunctioning gene become the same phenotype recessive epistasis need two copies to enable masking dog hair duplicate recessive epistasis two recessive alleles at either loci are capable of suppressing a phenotype o albinism o a is epi to B b is epi to A need both to be albino complementation test for recessive mutations o homozygous for different traits are crossed create heterozygote offspring o if allelic offspring will have only mutant allelesphenotype o if not allelic offspring will have mutant and wild type allele complementation groups 0 look for groups of 0 s non complementary I on same gene 0 in the chart stands for complementation dog coat example of multiple allele control 0 4 loci control dog coat color 0 Agouti locus I A s solid black I A w band yellow I A y yellow I A s saddle I A bicolor 0 Black pigment locus I B is black pigment I b is no black pigment 0 Extension I spatial expression of agouti I E solid I E m tan and black I E br tan and yellow 0 Spotting I 8 none I S j irish a lot I S p piebald less I S w extreme piebalding compound heterozygote individual who carries two different alleles at a locus resulting in a recessive phenotype sex influenced characteristics determined by autosomal genes expressed differently in males and females 0 higher penetrance in different sexes 0 ex beards and goats sexlimited characteristics trait has zero penetrance in other sex not expressed phenocopy environment alone can produce a phenotype that can be produced by a genotype Chapter 6 humans are bad subjects for genetic analysis 0 small progenies can t cross long generation time pedigree pictorial representation of a family history outlines inheritance of 1 or more characteristics STUDY CHART OF SYMBOLS autosomal recessive 0 occurs equally in males and females 0 skips generations need two alleles o happens often with closely related parents 0 ex Tay Sachs autosomal dominant 0 equal in both sexes 0 all who are affected have to have one parent who was affected 0 ex Huntington s Xlinked recessive o skips generations 0 males don t give to their sons only pass on the Y 0 females are often carriers 0 ex hemophilia Xlinked dominant 0 occurs in every generation 0 males pass to all girls but not boys Ylinked 0 only occurs in males 0 happens in every generation prenatal testing shows chromosomal abnormalities maternal blood test 0 look for alphafetoprotein too much shows neural tube defects 0 th and PAPPA ratio can lead to down syndrome 0 does NOT tell genetic problem tells if they are at RISK only ultrasound 0 direct visualization helps to guide amniocentesis 0 high frequency sound beams o can tell size neural tube defects skeletal abnormalities age sex amniocentesis 0 culture a few cells from amniotic fluid 0 have to grow outside of body in a lab CVS o chorionic villus sampling 0 larger sample don t need to spend time growing outside of body 0 done earlier than amniocentesis o aneuploidies are abnormal number of chromosomes often results in prenatal death 0 eggs sit in meiosis 1 for most of life the longer they sit the greater the chance for missegregation monosomies 1 copy which is lethal trisomies too much expression not always lethal Down Syndrome o trisomy in chromosome 21 o 97 are because of nondisjunction o 3 are chromosome 21 and chromosome 14 fusion 0 newborn screening mandatory for 29 conditions 0 metabolic diseases can be treated and prevented early 0 PKU o autosomal recessive o deficiency which leads to increased levels of phenylalanine which is harmful to central nervous system 0 can be prevented with special diet during youth 0 genetic counseling 0 helps people understand the implications medical psychological and familial of their genes 0 educational help promote informed choices 0 presymptomatic genetic testing test healthy adults for genes that may predispose them to genetic conditions huntington s breast cancer 0 heterozygote screening adultsmembers of a population to identify hetero carriers of certain diseases Tay Sachs genetic tests screen for most common mutation but not allrare complicated with incomplete penetranceenvironmental factors directtoconsumer tests genetic tests without health care provider Genetic Information Nondiscrimination Act prohibits health insurance companiesemployers from using genetic information Chapter 7 o linked genes are inherited together principle of segregation each diploid organism possesses two alleles at a locus that separate in meiosis o principle of independent assortment two alleles at a locus act independently of alleles at other loci o recombination sorting of alleles into new combinations 0 F1 may produce gametes with new combinations of alleles from its parents linked genes genes located close together on the same chromosome linkage group genes located together on the same chromosome travel together during meiosis o linkage and crossing over are opposites Wt W 1W 1 V9 notation written over two lines testcross also used for linkage o heterozygote for both traits nonrecombinant gametes gametes that contain only original combinations of alleles parental gametes nonrecombinant progeny progeny that display the original combination of traits present in parent generation 0 when genes are completely linked recombinant gametes new combinations of alleles 0 independent assortment recombinant progeny progeny that display new combinations of traits when there is a single crossover 0 half the gametes are recombinant and half are nonrecombinant frequency of recombinant gametes is always half the frequency of crossing over max proportion of recombinant gametes is 50 recombination frequency 0 percentage of recombinant progeny produced in a cross 0 number of recombinant progenytotal number of progeny times 100 coupling when wildtype alleles are found on one chromosome and mutant alleles found on the other repulsion each chromosome contains one wildtype and one mutant allele genetic maps chromosome maps calculated by using recombination physical maps chromosome maps calculated by using physical distances along chromosome distances on genetic maps measured in map units or centiMorgans cM three point cross technique for three gene cross 0 step 1 find the parental allele combinations highest frequency 0 step 2 double crossovers smallest frequency use to find gene order I gene order draw chromosome of heterozygous parent with all three possible gene orders compare I middle allele should differ from the alleles present in the nonrecombinant progeny 0 step 3 distance between closest pair I add up freq of next smallest plus freq of D00 and divide by total 0 step 4 distance between further pair I repeat step 3 0 step 5 distance between most distant pair I repeat but add up numerators from step 3 and step 4 then divide by total 0 step 6 calculate interference find expected by multiplying decimal answers in step 3 and step 4 find observed by adding up D00 and dividing by total interference 1 oe interference is the percent of double crossovers not observed single crossover 50 R 50 NR 2 strand double crossover all NR can t tell crossing over happened 3 strand double crossover 50 R 50 NR can t tell diff between single crossover 4 strand double crossover 100 R genetic markers variable genes with easily observable phenotypes for which inheritance can be studied
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'