Chapter 9 Patterns of Inheritance

Transcription

1 Chapte 9 Pattens of Inheitance PowePoint Lectues fo Campbell Biolog: Concepts & Connections, Seventh Edition eece, Talo, Simon, and Dicke 202 Peason Education, Inc. Lectue b Edwad J. Zalisko Intoduction Dogs ae one of man s longest genetic expeiments. Ove thousands of eas, humans have chosen and mated dogs with specific taits. The esult has been an incedibl divese aa of dogs with distinct bod tpes and behavioal taits. 202 Peason Education, Inc. Figue 9.0_ Chapte 9: Big Ideas Mendel s Laws Vaiations on Mendel s Laws The Chomosomal Basis of Inheitance Sex Chomosomes and Sex-Linked Genes

2 MENDEL S LAWS 202 Peason Education, Inc. 9. The science of genetics has ancient oots Pangenesis, poposed aound 400 BCE b Hippocates, was an eal explanation fo inheitance that suggested that paticles called pangenes came fom all pats of the oganism to be incopoated into eggs o spem and chaacteistics acquied duing the paents lifetime could be tansfeed to the offsping. Aistotle ejected pangenesis and agued that instead of paticles, the potential to poduce the taits was inheited. 202 Peason Education, Inc. 9. The science of genetics has ancient oots The idea that heedita mateials mix in foming offsping, called the blending hpothesis, was suggested in the 9th centu b scientists studing plants but late ejected because it did not explain how taits that disappea in one geneation can eappea in late geneations. 202 Peason Education, Inc. 2

3 9.2 Expeimental genetics began in an abbe gaden Heedit is the tansmission of taits fom one geneation to the next. Genetics is the scientific stud of heedit. Gego Mendel began the field of genetics in the 60s, deduced the pinciples of genetics b beeding gaden peas, and elied upon a backgound of mathematics, phsics, and chemist. 202 Peason Education, Inc. 9.2 Expeimental genetics began in an abbe gaden In 66, Mendel coectl agued that paents pass on to thei offsping discete heitable factos and stessed that the heitable factos (toda called genes), etain thei individualit geneation afte geneation. A heitable featue that vaies among individuals, such as flowe colo, is called a chaacte. Each vaiant fo a chaacte, such as puple o white flowes, is a tait. 202 Peason Education, Inc. 9.2 Expeimental genetics began in an abbe gaden Tue-beeding vaieties esult when self-fetilization poduces offsping all identical to the paent. The offsping of two diffeent vaieties ae hbids. The coss-fetilization is a hbidization, o genetic coss. Tue-beeding paental plants ae the P geneation. Hbid offsping ae the F geneation. A coss of F plants poduces an F 2 geneation. 202 Peason Education, Inc. 3

4 Figue 9.2B Petal Capel Stamen Figue 9.2C_s emoval of stamens White Capel Paents (P) Stamens 2 Tansfe Puple of pollen Figue 9.2C_s2 emoval of stamens White Capel Paents (P) Stamens 2 Tansfe Puple of pollen 3 Capel matues into pea pod 4

5 Figue 9.2C_s3 emoval of stamens White Capel Paents (P) Stamens 2 Tansfe Puple of pollen 3 Capel matues into pea pod 4 Seeds fom pod planted Offsping (F ) Figue 9.2D Chaacte Dominant Taits ecessive Flowe colo Puple White Flowe position Axial Teminal Seed colo ellow Geen Seed shape ound Winkled Pod shape Inflated Consticted Pod colo Geen ellow Stem length Tall Dwaf 9.3 Mendel s law of segegation descibes the inheitance of a single chaacte A coss between two individuals diffeing in a single chaacte is a monohbid coss. Mendel pefomed a monohbid coss between a plant with puple flowes and a plant with white flowes. The F geneation poduced all plants with puple flowes. A coss of F plants with each othe poduced an F 2 geneation with ¾ puple and ¼ white flowes. 202 Peason Education, Inc. 5

6 Figue 9.3A_s The Expeiment P geneation (tue-beeding paents) Puple flowes White flowes Figue 9.3A_s2 The Expeiment P geneation (tue-beeding paents) Puple flowes White flowes F geneation All plants have puple flowes Figue 9.3A_s3 The Expeiment P geneation (tue-beeding paents) Puple flowes White flowes F geneation F 2 geneation All plants have puple flowes Fetilization among F plants (F F ) 3 of plants 4 have puple flowes of plants 4 have white flowes 6

7 9.3 Mendel s law of segegation descibes the inheitance of a single chaacte The all-puple F geneation did not poduce light puple flowes, as pedicted b the blending hpothesis. Mendel needed to explain wh white colo seemed to disappea in the F geneation and white colo eappeaed in one quate of the F 2 offsping. Mendel obseved the same pattens of inheitance fo six othe pea plant chaactes. 202 Peason Education, Inc. 9.3 Mendel s law of segegation descibes the inheitance of a single chaacte Mendel developed fou hpotheses, descibed below using moden teminolog.. Alleles ae altenative vesions of genes that account fo vaiations in inheited chaactes. 2. Fo each chaacteistic, an oganism inheits two alleles, one fom each paent. The alleles can be the same o diffeent. A homozgous genotpe has identical alleles. A heteozgous genotpe has two diffeent alleles. 202 Peason Education, Inc. 9.3 Mendel s law of segegation descibes the inheitance of a single chaacte 3. If the alleles of an inheited pai diffe, then one detemines the oganism s appeaance and is called the dominant allele. The othe has no noticeable effect on the oganism s appeaance and is called the ecessive allele. The phenotpe is the appeaance o expession of a tait. The genotpe is the genetic makeup of a tait. The same phenotpe ma be detemined b moe than one genotpe. 202 Peason Education, Inc. 7

8 9.3 Mendel s law of segegation descibes the inheitance of a single chaacte 4. A spem o egg caies onl one allele fo each inheited chaacte because allele pais sepaate (segegate) fom each othe duing the poduction of gametes. This statement is called the law of segegation. Mendel s hpotheses also explain the 3: atio in the F 2 geneation. The F hbids all have a Pp genotpe. A Punnett squae shows the fou possible combinations of alleles that could occu when these gametes combine. 202 Peason Education, Inc. Figue 9.3B_s The Explanation P geneation Genetic makeup (alleles) Puple flowes White flowes PP pp Gametes All P All p Figue 9.3B_s2 The Explanation P geneation Genetic makeup (alleles) Puple flowes White flowes PP pp Gametes All P All p F geneation (hbids) All Pp Gametes 2 P 2 p

9 Figue 9.3B_s3 The Explanation P geneation Genetic makeup (alleles) Puple flowes White flowes PP pp Gametes All P All p F geneation (hbids) F 2 geneation Gametes Fetilization 2 P P All Pp Alleles segegate Spem fom F plant p 2 p Phenotpic atio 3 puple : white Genotpic atio PP : 2 Pp : pp P Eggs fom F plant p PP Pp Pp pp Figue 9.3B_4 F 2 geneation Spem fom F plant P p Phenotpic atio 3 puple : white Genotpic atio PP : 2 Pp : pp P Eggs fom F plant p PP Pp Pp pp 9.4 Homologous chomosomes bea the alleles fo each chaacte A locus (plual, loci) is the specific location of a gene along a chomosome. Fo a pai of homologous chomosomes, alleles of a gene eside at the same locus. Homozgous individuals have the same allele on both homologues. Heteozgous individuals have a diffeent allele on each homologue. 202 Peason Education, Inc. 9

10 Figue 9.4 P Gene loci a B Dominant allele Homologous chomosomes P Genotpe: PP aa Bb Homozgous Homozgous fo the fo the dominant ecessive allele allele a b ecessive allele Heteozgous, with one dominant and one ecessive allele 9.5 The law of independent assotment is evealed b tacking two chaactes at once A dihbid coss is a mating of paental vaieties that diffe in two chaactes. Mendel pefomed the following dihbid coss with the following esults: P geneation: ound ellow seeds winkled geen seeds F geneation: all plants with ound ellow seeds F 2 geneation: 9/6 had ound ellow seeds 3/6 had winkled ellow seeds 3/6 had ound geen seeds /6 had winkled geen seeds 202 Peason Education, Inc. Figue 9.5A P geneation Gametes F geneation Spem F 2 geneation Eggs 2 The hpothesis of dependent assotment Data did not suppot; hpothesis efuted Spem Eggs The hpothesis of independent assotment Actual esults; hpothesis suppoted ellow ound Geen ound ellow winkled Geen winkled 0

11 Figue 9.5B Blind Blind Phenotpes Genotpes Black coat, nomal vision B_N_ Black coat, blind (PA) B_nn Chocolate coat, nomal vision bbn_ Chocolate coat, blind (PA) bbnn Mating of double heteozgotes (black coat, nomal vision) BbNn BbNn Blind Blind Phenotpic atio of the offsping 9 Black coat, nomal vision 3 Black coat, blind (PA) 3 Chocolate coat, nomal vision Chocolate coat, blind (PA) 9.5 The law of independent assotment is evealed b tacking two chaactes at once Mendel needed to explain wh the F 2 offsping had new nonpaental combinations of taits and a 9:3:3: phenotpic atio. Mendel suggested that the inheitance of one chaacte has no effect on the inheitance of anothe, suggested that the dihbid coss is the equivalent to two monohbid cosses, and called this the law of independent assotment. 202 Peason Education, Inc. 9.5 The law of independent assotment is evealed b tacking two chaactes at once The following figue demonstates the law of independent assotment as it applies to two chaactes in Labado etieves: black vesus chocolate colo, nomal vision vesus pogessive etinal atoph. 202 Peason Education, Inc.

12 9.6 Geneticists can use the testcoss to detemine unknown genotpes A testcoss is the mating between an individual of unknown genotpe and a homozgous ecessive individual. A testcoss can show whethe the unknown genotpe includes a ecessive allele. Mendel used testcosses to veif that he had tuebeeding genotpes. The following figue demonstates how a testcoss can be pefomed to detemine the genotpe of a Lab with nomal ees. 202 Peason Education, Inc. Figue 9.6 What is the genotpe of the black dog? Testcoss Genotpes B_? bb Two possibilities fo the black dog: BB o Bb Gametes B B b b Bb b Bb bb Offsping All black black : chocolate 9.7 Mendel s laws eflect the ules of pobabilit Using his stong backgound in mathematics, Mendel knew that the ules of mathematical pobabilit affected the segegation of allele pais duing gamete fomation and the e-foming of pais at fetilization. The pobabilit scale anges fom 0 to. An event that is cetain has a pobabilit of and cetain not to occu has a pobabilit of Peason Education, Inc. 2

13 9.7 Mendel s laws eflect the ules of pobabilit The pobabilit of a specific event is the numbe of was that event can occu out of the total possible outcomes. Detemining the pobabilit of two independent events uses the ule of multiplication, in which the pobabilit is the poduct of the pobabilities fo each event. The pobabilit that an event can occu in two o moe altenative was is the sum of the sepaate pobabilities, called the ule of addition. 202 Peason Education, Inc. Figue 9.7 F genotpes Bb female Bb male Fomation of eggs Fomation of spem 2 B ( 2 2 ) 2 Spem b F 2 genotpes 2 B B B B Eggs 4 4 b 2 b b B b b CONNECTION: Genetic taits in humans can be tacked though famil pedigees In a simple dominant-ecessive inheitance of dominant allele A and ecessive allele a, a ecessive phenotpe alwas esults fom a homozgous ecessive genotpe (aa) but a dominant phenotpe can esult fom eithe the homozgous dominant genotpe (AA) o a heteozgous genotpe (Aa). Wild-tpe taits, those pevailing in natue, ae not necessail specified b dominant alleles. 202 Peason Education, Inc. 3

14 Figue 9.A Dominant Taits ecessive Taits Feckles No feckles Widow s peak Staight hailine Fee ealobe Attached ealobe 9. CONNECTION: Genetic taits in humans can be tacked though famil pedigees The inheitance of human taits follows Mendel s laws. A pedigee shows the inheitance of a tait in a famil though multiple geneations, demonstates dominant o ecessive inheitance, and can also be used to deduce genotpes of famil membes. 202 Peason Education, Inc. Figue 9.B Fist geneation (gandpaents) Ff Ff ff Ff Second geneation (paents, aunts, and uncles) FF o Ff Thid geneation (two sistes) Female Male Attached Fee ff ff Ff Ff ff ff FF o Ff 4

15 9.9 CONNECTION: Man inheited disodes in humans ae contolled b a single gene Inheited human disodes show eithe. ecessive inheitance in which two ecessive alleles ae needed to show disease, heteozgous paents ae caies of the disease-causing allele, and the pobabilit of inheitance inceases with inbeeding, mating between close elatives. 2. dominant inheitance in which one dominant allele is needed to show disease and dominant lethal alleles ae usuall eliminated fom the population. 202 Peason Education, Inc. Figue 9.9A Paents Nomal Dd Nomal Dd D Spem d D DD Nomal Dd Nomal (caie) Offsping Eggs d Dd Nomal (caie) dd Deaf 9.9 CONNECTION: Man inheited disodes in humans ae contolled b a single gene The most common fatal genetic disease in the United States is cstic fibosis (CF), esulting in excessive thick mucus secetions. The CF allele is ecessive and caied b about in 3 Ameicans. Dominant human disodes include achondoplasia, esulting in dwafism, and Huntington s disease, a degeneative disode of the nevous sstem. 202 Peason Education, Inc. 5

16 Table CONNECTION: New technologies can povide insight into one s genetic legac New technologies offe was to obtain genetic infomation befoe conception, duing pegnanc, and afte bith. Genetic testing can identif potential paents who ae heteozgous caies fo cetain diseases. 202 Peason Education, Inc. 9.0 CONNECTION: New technologies can povide insight into one s genetic legac Seveal technologies can be used fo detecting genetic conditions in a fetus. Amniocentesis extacts samples of amniotic fluid containing fetal cells and pemits kaotping and biochemical tests on cultued fetal cells to detect othe conditions, such as Ta-Sachs disease. Choionic villus sampling emoves a sample of choionic villus tissue fom the placenta and pemits simila kaotping and biochemical tests. 202 Peason Education, Inc. 6

17 Figue 9.0A Ultasound tansduce Amniocentesis Amniotic fluid extacted Choionic Villus Sampling (CVS) Tissue extacted Ultasound fom the tansduce choionic villi Fetus Placenta Uteus Cevix Fetus Placenta Choionic villi Cevix Centifugation Uteus Amniotic fluid Fetal cells Cultued cells Seveal hous Seveal weeks Biochemical and genetics tests Fetal cells Seveal hous Seveal weeks Seveal hous Kaotping 9.0 CONNECTION: New technologies can povide insight into one s genetic legac Blood tests on the mothe at 4 20 weeks of pegnanc can help identif fetuses at isk fo cetain bith defects. Fetal imaging enables a phsician to examine a fetus diectl fo anatomical defomities. The most common pocedue is ultasound imaging, using sound waves to poduce a pictue of the fetus. Newbon sceening can detect diseases that can be pevented b special cae and pecautions. 202 Peason Education, Inc. 9.0 CONNECTION: New technologies can povide insight into one s genetic legac New technologies aise ethical consideations that include the confidentialit and potential use of esults of genetic testing, time and financial costs, and detemining what, if anthing, should be done as a esult of the testing. 202 Peason Education, Inc. 7

18 VAIATIONS ON MENDEL S LAWS 202 Peason Education, Inc. 9. Incomplete dominance esults in intemediate phenotpes Mendel s pea cosses alwas looked like one of the paental vaieties, called complete dominance. Fo some chaactes, the appeaance of F hbids falls between the phenotpes of the two paental vaieties. This is called incomplete dominance, in which neithe allele is dominant ove the othe and expession of both alleles occus. 202 Peason Education, Inc. Figue 9.A P geneation ed Gametes White F geneation Pink hbid Gametes 2 2 F 2 geneation 2 Spem 2 Eggs 2 2

19 9. Incomplete dominance esults in intemediate phenotpes Incomplete dominance does not suppot the blending hpothesis because the oiginal paental phenotpes eappea in the F 2 geneation. One example of incomplete dominance in humans is hpecholesteolemia, in which dangeousl high levels of cholesteol occu in the blood and heteozgotes have intemediatel high cholesteol levels. 202 Peason Education, Inc. Figue 9.B LDL ecepto HH Homozgous fo abilit to make LDL eceptos LDL Genotpes Hh hh Heteozgous Homozgous fo inabilit to make LDL eceptos Phenotpes Cell Nomal Mild disease Sevee disease 9.2 Man genes have moe than two alleles in the population Although an individual can at most ca two diffeent alleles fo a paticula gene, moe than two alleles often exist in the wide population. Human ABO blood goup phenotpes involve thee alleles fo a single gene. The fou human blood goups, A, B, AB, and O, esult fom combinations of these thee alleles. The A and B alleles ae both expessed in heteozgous individuals, a condition known as codominance. 202 Peason Education, Inc. 9

20 9.2 Man genes have moe than two alleles in the population In codominance, neithe allele is dominant ove the othe and expession of both alleles is obseved as a distinct phenotpe in the heteozgous individual. AB blood tpe is an example of codominance. 202 Peason Education, Inc. Figue 9.2 Blood Goup (Phenotpe) Genotpes Cabohdates Pesent on ed Blood Cells Antibodies Pesent in Blood eaction When Blood fom Goups Below Is Mixed with Antibodies fom Goups at Left O A B AB A I A I A o I A i Cabohdate A Anti-B B I B I B o I B i Cabohdate B Anti-A Cabohdate A AB I A I B and Cabohdate B None O ii Neithe Anti-A Anti-B No eaction Clumping eaction 9.3 A single gene ma affect man phenotpic chaactes Pleiotop occus when one gene influences man chaacteistics. Sickle-cell disease is a human example of pleiotop. This disease affects the tpe of hemoglobin poduced and the shape of ed blood cells and causes anemia and ogan damage. Sickle-cell and nonsickle alleles ae codominant. Caies of sickle-cell disease ae esistant to malaia. 202 Peason Education, Inc. 20

21 Figue 9.3A Figue 9.3B An individual homozgous fo the sickle-cell allele Poduces sickle-cell (abnomal) hemoglobin The abnomal hemoglobin cstallizes, causing ed blood cells to become sickle-shaped Sickled cell The multiple effects of sickled cells Damage to ogans Kidne failue Heat failue Spleen damage Bain damage (impaied mental function, paalsis) Othe effects Pain and feve Joint poblems Phsical weakness Anemia Pneumonia and othe infections 9.4 A single chaacte ma be influenced b man genes Man chaacteistics esult fom polgenic inheitance, in which a single phenotpic chaacte esults fom the additive effects of two o moe genes. Human skin colo is an example of polgenic inheitance. 202 Peason Education, Inc. 2

22 Figue 9.4 P geneation aabbcc AABBCC (ve light) (ve dak) F geneation AaBbCc AaBbCc Spem F 2 geneation Eggs Faction of population Skin colo 9.5 The envionment affects man chaactes Man chaactes esult fom a combination of heedit and the envionment. Fo example, skin colo is affected b exposue to sunlight, susceptibilit to diseases, such as cance, has heedita and envionmental components, and identical twins show some diffeences. Onl genetic influences ae inheited. 202 Peason Education, Inc. THE CHOMOSOMAL BASIS OF INHEITANCE 202 Peason Education, Inc. 22

23 9.6 Chomosome behavio accounts fo Mendel s laws The chomosome theo of inheitance states that genes occup specific loci (positions) on chomosomes and chomosomes undego segegation and independent assotment duing meiosis. 202 Peason Education, Inc. 9.6 Chomosome behavio accounts fo Mendel s laws Mendel s laws coelate with chomosome sepaation in meiosis. The law of segegation depends on sepaation of homologous chomosomes in anaphase I. The law of independent assotment depends on altenative oientations of chomosomes in metaphase I. 202 Peason Education, Inc. Figue 9.6_s F geneation All ellow ound seeds () Metaphase I of meiosis 23

24 Figue 9.6_s2 F geneation All ellow ound seeds () Metaphase I of meiosis Anaphase I Metaphase II Figue 9.6_s3 F geneation All ellow ound seeds () Metaphase I of meiosis Anaphase I Metaphase II Gametes Fetilization F 2 geneation 9 :3 :3 : Figue 9.6_4 Spem Eggs ellow ound 3 6 Geen ound 3 6 ellow winkled 6 Geen winkled 24

25 9.7 SCIENTIFIC DISCOVE: Genes on the same chomosome tend to be inheited togethe Bateson and Punnett studied plants that did not show a 9:3:3: atio in the F 2 geneation. What the found was an example of linked genes, which ae located close togethe on the same chomosome and tend to be inheited togethe. 202 Peason Education, Inc. Figue 9.7_ The Expeiment Puple flowe PpLl PpLl Long pollen Phenotpes Puple long Puple ound ed long ed ound Obseved offsping Pediction (9:3:3:) Figue 9.7_2 The Explanation: Linked Genes Paental diploid cell PpLl P L p l Meiosis Most gametes P L p l Fetilization P L PL Most P L offsping Eggs p l pl P L Spem PL pl P L p l p l p l 3 puple long : ed ound Not accounted fo: puple ound and ed long 25

26 9. SCIENTIFIC DISCOVE: Cossing ove poduces new combinations of alleles Cossing ove between homologous chomosomes poduces new combinations of alleles in gametes. Linked alleles can be sepaated b cossing ove, foming ecombinant gametes. The pecentage of ecombinants is the ecombination fequenc. 202 Peason Education, Inc. Figue 9.A P L p L p l p l Tetad (pai of homologous chomosomes) Cossing ove Paental gametes p L P l ecombinant gametes Figue 9.C_ The Expeiment Ga bod, long wings (wild tpe) GgLl Female Black bod, vestigial wings ggll Male Offsping: Ga long Black vestigial Ga vestigial Black long Paental phenotpes ecombinant phenotpes 39 ecombinants ecombination fequenc = = 0.7 o 7% 2,300 total offsping 26

27 Figue 9.C_2 The Explanation GgLl Female G L g l Cossing ove g l g l ggll Male G L g l G l g L g l Eggs Spem G L g l Offsping g l G l g l g l g L g l Paental ecombinant 9.9 Geneticists use cossove data to map genes When examining ecombinant fequenc, Mogan and his students found that the geate the distance between two genes on a chomosome, the moe points thee ae between them whee cossing ove can occu. ecombination fequencies can thus be used to map the elative position of genes on chomosomes. 202 Peason Education, Inc. Figue 9.9A Section of chomosome caing linked genes g c l 7% 9% 9.5% ecombination fequencies 27

28 Figue 9.9B Shot aistae Mutant phenotpes Black bod (g) Cinnaba ees (c) Vestigial wings (l) Bown ees Long aistae (appendages on head) Ga bod (G) ed ees (C) Wild-tpe phenotpes Nomal wings (L) ed ees SEX CHOMOSOMES AND SEX-LINKED GENES 202 Peason Education, Inc Chomosomes detemine sex in man species Man animals have a pai of sex chomosomes, designated X and, that detemine an individual s sex. In mammals, males have X sex chomosomes, females have XX sex chomosomes, the chomosome has genes fo the development of testes, and an absence of the allows ovaies to develop. 202 Peason Education, Inc. 2

29 Figue 9.20A X Figue 9.20B Paents (diploid) Male 44 + X Female 44 + XX Gametes (haploid) 22 + X Spem X Egg Offsping (diploid) 44 + XX Female 44 + X Male Figue 9.2A 29

30 Figue 9.2A_ Figue 9.2A_2 Figue 9.2B Female Male X X X X Spem Eggs X X X X = ed-ee allele = white-ee allele 30

31 Figue 9.2C Female Male X X X Spem x Eggs X X X X X X X X = ed-ee allele = white-ee allele Figue 9.2D Female Male X X X X Spem Eggs X X X X X X X X = ed-ee allele = white-ee allele 9.22 CONNECTION: Human sex-linked disodes affect mostl males Most sex-linked human disodes ae due to ecessive alleles and seen mostl in males. A male eceiving a single X-linked ecessive allele fom his mothe will have the disode. A female must eceive the allele fom both paents to be affected. 202 Peason Education, Inc. 3

32 9.22 CONNECTION: Human sex-linked disodes affect mostl males ecessive and sex-linked human disodes include hemophilia, chaacteized b excessive bleeding because hemophiliacs lack one o moe of the poteins equied fo blood clotting, ed-geen colo blindness, a malfunction of lightsensitive cells in the ees, and Duchenne muscula dstoph, a condition chaacteized b a pogessive weakening of the muscles and loss of coodination. 202 Peason Education, Inc. Figue 9.22 Queen Victoia Albet Alice Louis Alexanda Cza Nicholas II of ussia Alexis Female Male Hemophilia Caie Nomal 9.23 EVOLUTION CONNECTION: The chomosome povides clues about human male evolution The chomosome povides clues about human male evolution because chomosomes ae passed intact fom fathe to son and mutations in chomosomes can eveal data about ecent shaed ancest. 202 Peason Education, Inc. 32