Chapter 9 ppt

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Patterns of Inheritance

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Chapter 9 ppt

  1. 1. Purebreds and Mutts–A Difference of Heredity • Purebred dogs – Variation? – Selective breeding?Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  2. 2. • Mutts, or mixed breed dogs on the other hand – Genetic variation? More? …less? Why?Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  3. 3. • Modern Experimental Genetics – Gregor Mendel’s quantitative experiments with pea plants Petal Stamen Carpel Figure 9.2 A Figure 9.2 BCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  4. 4. • Mendel crossed? ..bred? …pea plants that differed in certain characteristics • WHY? – And traced traits from generation to generation WHY?Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  5. 5. Flower color Purple White • Mendel hypothesized that there are alternative forms of genes – The units that determine heritable traits Flower position Axial Terminal Seed color Yellow Green Seed shape Round Wrinkled Pod shape Inflated Constricted Pod color Green Yellow Stem length Tall DwarfCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  6. 6. Mendel’s Law’s: P generation (true-breeding parents) × 2)Dominance Purple flowers White flowers 3)Segregation From his experimental data F1 generation All plants have purple flowers – Mendel deduced that an organism has two genes (alleles) for each inherited characteristic Fertilization among F1 plants (F1 × F1) F2 generation 3 1 4 4 of plants of plants have purple flowers have white flowersCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  7. 7. • For each characteristic – An organism inherits two alleles, one from each parent – Hmmm…does this remind you of anything we studied? …what? Be Specific!Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  8. 8. P plants Genetic makeup (alleles) PP pp • Mendel’s law of segregation Gametes – Predicts that allele pairs separate from All P All p each other during the production of gametes F1 plants (hybrids) All Pp 1 1 2 P 2 p Gametes Sperm P p F2 plants Phenotypic ratio 3 purple : 1 white P PP Pp Eggs Genotypic ratio 1 PP : 2 Pp: 1 pp p Pp pp Figure 9.3 BCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  9. 9. Recal….Homologous chromosomes bear the two alleles for each characteristic • Alternative forms of a gene – Reside at the same locus on homologous chromosomes Gene loci Dominant allele P a B P a b Recessive allele Genotype: PP aa Bb Homozygous Homozygous Heterozygous for the for the dominant allele recessive alleleCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  10. 10. Hypothesis: Dependent assortment Hypothesis: Independent assortment P generation RRYY rryy RRYY rryy • Mendel’s law of independent assortment – States that alleles of a pair segregate independently Gametes RY ry Gametes RY × ry of other allele pairs during gamete formation RrYy RrYy F1 generation Sperm Sperm 1 1 1 1 RY ry RY ry 1 1 4 4 4 4 2 RY 2 ry 1 1 4 RY F2 generation 2 RY RRYY RrYY RRYy RrYy Eggs 1 4 ry 1 2 ry RrYY rrYY RrYy rrYy Eggs Yellow 1 9 round 4 Ry 16 RRYy RrYy RRyy Rryy Green 3 round 16 1 4 ry Actual results Yellow 3 contradict hypothesis RrYy rrYy Rryy rryy wrinkled 16 Actual results 1 Green support hypothesis 16 wrinkledCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  11. 11. • An example of independent assortment • Punnett Squares, Probablility & Predicting F1 & F2 Blind Blind Phenotypes Black coat, normal vision Black coat, blind (PRA) Chocolate coat, normal vision Chocolate coat, blind (PRA) Genotypes B_N_ B_nn bbN_ bbnn Mating of heterozygotes BbNn × BbNn (black, normal vision) Phenotypic ratio 9 black coat, 3 black coat, 3 chocolate coat, 1 chocolate coat, normal vision blind (PRA) normal vision blind (PRA) of offspringFigure 9.5 B PRA: Progressive Retinal AtrophyCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  12. 12. Geneticists a testcross to determine unknown genotypes • The offspring of a testcross, a mating between an individual × Testcross: of unknown genotype and a homozygous recessive individual Genotypes B_ bb Two possibilities for the black dog: BB or Bb Gametes B B b b Bb b Bb bb Offspring All black 1 black : 1 chocolateCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  13. 13. Mendel’s laws reflect the….. RULES OF PROBABILITY • Inheritance follows the rules of probability Could you use a test cross to determine if an organism was true breeding or pure breeding? How?Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  14. 14. F1 genotypes • The Mule of Multiplication, OR …the Product Rule Bb male Formation of sperm – Calculates the probability of two independent events • The Rule of Addition Bb female – Calculateseggs probability of an event that can occur Formation of the in alternate ways 1 1 2 B 2 b 1 B B B b 2 B 1 1 4 4 F2 genotypes 1 b B b b 2 b 1 1 4 4 Figure 9.7Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  15. 15. • Family pedigrees – Can be used to determine individual genotypes Dd Dd D? D? Joshua Abigail John Hepzibah Lambert Linnell Eddy Daggett D? dd Dd Abigail Jonathan Elizabeth Lambert Lambert Eddy Dd Dd dd Dd Dd Dd dd Female Male Deaf Hearing Comet Hale Bopp seen from path to Lambert’s Cove Beach…Martha’s Vineyard Figure 9.8 BCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  16. 16. CONNECTION 9.9 Many inherited disorders in humans are controlled by a single gene • Some autosomal disorders in humans Table 9.9Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  17. 17. Recessive Disorders • Most human genetic disorders are recessive Parents Normal Normal × Dd Dd Sperm D d Dd D DD Normal Normal (carrier) Offspring Eggs Dd dd d Normal Deaf (carrier) Figure 9.9 ACopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  18. 18. Dominant Disorders• Some human genetic disorders are dominant• http://www.youtube.com/watch?v=zS7vCd8KQIA• http://en.wikipedia.org/wiki/Human_genetics#Autosomal_dominant_inheritance Figure 9.9 BCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  19. 19. CONNECTION New technologies can provide insight into one’s genetic legacy • New technologies – Can provide insight for reproductive decisionshttp://www.gaucherdisease.com/Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  20. 20. Fetal Testing • Amniocentesis and chorionic villus sampling (CVS) – Allow doctors to remove fetal cells that can be tested for genetic abnormalities Amniocentesis Chorionic villus sampling (CVS) Ultrasound Needle inserted monitor through abdomen to Ultrasound Suction tube inserted extract amniotic fluid monitor through cervix to extract tissue from chorionic villi Fetus Fetus Placenta Placenta Chorionic Uterus villi Cervix Cervix Uterus Amniotic fluid Centrifugation Fetal Fetal cells cells Biochemical tests Several Several weeks hours KaryotypingCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  21. 21. Fetal Imaging • Ultrasound imaging – Uses sound waves to produce a picture of the fetusCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  22. 22. NON-MENDELIAN INHERITANCE Genotype = Phenotype? 2)What does this mean? 3)Mendel’s principles are valid for all sexually reproducing species 4)D’OH…. genotype often does not dictate phenotype in the simple way his laws describeCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  23. 23. Genotypes: Incomplete Dominance? P generation When an offspring’s phenotype × in between the phenotypes of its parents, it Red HH is Hh White hh exhibits incompleteto make RR dominance. Homozygous Heterozygous rr Homozygous for ability for inability to make LDL receptors LDL receptors Gametes R r F1 generation Phenotypes: Pink Rr LDL 1 1 Gametes 2 R 2 r LDL receptor Sperm 1 1 2 R 2 r 1 Red Pink Cell R rR 2 RR F2 generation Eggs 1 Normalr Pink White Mild disease Severe disease 2 Rr rr Figure 9.12 BCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  24. 24. Multiple Alleles!! • In a population – Multiple alleles often exist for a characteristicCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  25. 25. • The ABO blood type in humans – Involves three alleles of a single gene • The alleles for A and B blood types are codominant – And both are expressed in the phenotype Blood Antibodies Reaction When Blood from Groups Below Is Mixed with Group Present in Antibodies from Groups at Left (Phenotype) Genotypes Blood O A B AB O ii Anti-A Anti-B IAIA A or Anti-B IAi IBIB B or Anti-A IBi AB IAIB — Figure 9.13Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  26. 26. Pleiotropy: A single gene may affect many phenotypic characteristics •Pleiotropy describes the genetic effect of a single gene on multiple phenotypic traits. The underlying mechanism is that the gene codes for a product that is, for example, used by various cells, or has a signaling function on various targets. PKU (phenylketonuria) Symptoms: mental retardation reduced hair skin pigmentation, …caused by any of a large number of mutations in a single gene that codes for the enzyme (phenylalanine hydroxylase), which converts the amino acid phenylalanine to tyrosine, another amino acid. Depending on the mutation involved, this results in reduced or zero conversion of phenylalanine to tyrosine, and phenylalanine concentrations increase to toxic levels, causing damage at several locations in the body. PKU is totally benign if a diet free from phenylalanine is maintainedCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  27. 27. A single characteristic may be influenced by many genes • Polygenic inheritance: Creates a continuum of phenotypes http://www.athro.com/evo/inherit.html In humans three genes involved in eye color are known. They explain typical patterns of inheritance of brown, green, and blue eye colors. However, they dont explain everything. Grey eye color, Hazel eye color, and multiple shades of blue, brown, green, and grey are not explained. The molecular basis of these genes is not known. What proteins they produce and how these proteins produce eye color is not known. Eye color at birth is often blue, and later turns to a darker color. Why eye color can change over time is not known. An additional gene for green is also postulated, and there are reports of blue eyed parents producing brown eyed children (which the three known genes cant easily explain [mutations, modifier genes that supress brown, and additional brown genes are all potential explanations]). The known Human Eye color genes are: EYCL1 (also called gey), the Green/blue eye color gene, located on chromosome 19 (though there is also evidence that another gene with similar activity exists but is not on chromosome 19). EYCL2 (also called bey1), the central brown eye color gene, possibly located on chromosome 15. EYCL3 (also called bey2), the Brown/blue eye color gene located on chromosome 15. EYCL3 probably involves mutations in the regulatory region just before the OCA2 gene (which produces a protein that is expressed in melanocytes). A second gene for green has also been postulated. Other eye colors including grey and hazel are not yet explained. We do not yet know what these genes make, or how they produce eye colors. The two gene model (EYCL1 and EYCL3) used above explains only a portion of human eye color inheritance. Both additional eye color genes and modifier genes are almost certainly involvedCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  28. 28. The environmental affects many characteristics • Many traits are affected, in varying degrees – By both genetic and environmental factorsCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  29. 29. Designer Babies? • Genetic testing can detect disease-causing alleles • Predictive genetic testing – May inform people of their risk for developing genetic diseases – http://www.wired.com/wiredscience/2009/03/designerdebate/ – http://www.geneticsandsociety.org/article.php?id=4561Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  30. 30. THE CHROMOSOMAL BASIS OF INHERITANCE Chromosome behavior accounts for Mendel’s laws • The structure and assembly of a eukaryotic chromosome: http://www.youtube.com/watch?v=gbSIBhFwQ4s • Genes are located on chromosomes – Whose behavior during meiosis and fertilization accounts for inheritance patternsCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  31. 31. • The chromosomal basis of Mendel’s laws F1 generation All round yellow seeds (RrYy) R r y Y R r r R Metaphase I Y y of meiosis Y y (alternative arrangements) R r r R Anaphase I Y y of meiosis Y y R r r R Metaphase II of meiosis Y y Y y Y y Y Y Y y y Gametes y R R r r r r R R 1 1 1 1 RY ry rY Ry 4 4 4 4 Fertilization among the F1 plants F2 generation 9 :3 :3 :1 (See Figure 9.5A)Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  32. 32. Experiment Genes on the same chromosome tend to be inherited Purple flower together PpLI × PpLI Long pollen Observed Prediction Phenotypes offspring (9:3:3:1) • Certain genes are linked Purple long Purple round 284 21 215 71 Red long 21 71 Red round 55 24 – They tend to be inherited Explanation: linked genes together because they Parental PL reside close together on diploid cell PpLI PI the same chromosome Meiosis Most PL PI gametes Dominant or Trait A Trait B Fertilization References Sperm Recessive Blond hair Blue eyes PL both recessive PI [5] PL PL PL A is recessive B is Flexibility Anxiety disorderL Most P PI [6] offspring Eggs PI dominant PI PI Large ears broad nose PL both dominant PI [7] 3 purple long : 1 red round Not accounted for: purple round and red long Figure 9.19Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  33. 33. Crossing over produces new combinations of alleles??? HOW? • Crossing over can separate linked alleles – Producing gametes with recombinant chromosomes A B a b A B a b A b a B Tetrad Crossing over GametesCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  34. 34. • Thomas Hunt Morgan – Performed some of the early studies of crossing over using the fruit fly Drosophila melanogasterCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  35. 35. Thomas Hunt Morgan • Morgan began working seriously with Drosophila in 1907. • But despite much effort and the breeding of successive generations, Morgan initially failed to detect a single mutation. "Two years work wasted," he lamented to one visitor to his laboratory. "I have been breeding those flies for all that time and Ive got nothing out of it."(Harrison, R.G., "Embryology and Its Relations") • April 1910 he suddenly had a breakthrough…one male fly with white : How did this white eye color originate? What determines eye color? • Morgan bred this white-eyed (mutant) male to a red-eyed (wild-type) virgin sister and found that white-colored eyes are inherited in a special way. In the first generation of brother-sister mating, labeled F1, there were only red-eyed offspring, suggesting that red eye color is dominant and that white eye color is recessive. To prove this idea Morgan carried out brother-sister matings with the next generation (F2) and found that the offspring followed the expected Mendelian ratio for a recessive trait: three red-eyed flies to every one white- eyed fly. With these experiments Morgan started a tradition, which continues to this day, whereby he named the gene "white" by the result of its mutation. But then came a surprise. He had expected there would be an equal number of males and females with white eyes, but it turned out that all the female flies had red eyes; only males had white eyes, and, even more, only some of them displayed the trait. Morgan realized that white eye color is not only recessive but is also linked in some way to sex.Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  36. 36. Morgan…continued • By 1910, it was already known that chromosomes occur in pairs and that Drosophila had four pairs of chromosomes. Several decades earlier, these thread-shaped structures had been seen under a microscope to be located in the nucleus, but nobody knew their function. Morgan later was to describe them in the following terms: •"The egg of every species of animal or plant carries a definite number of bodies called chromosomes. The sperm carries the same number. Consequently, when the sperm unites with the egg, the fertilized egg will contain the double number of chromosomes. For each chromosome contributed by the sperm there is a corresponding chromosome contributed by the egg, i.e., there are two chromosomes of each kind, which together constitute a pair." (Morgan, T.H. et al., The Mechanism of Mendelian Heredity) When Morgan turned to examining the fruit flys chromosomes under the microscope, he immediately appreciated that not all four pairs of chromosomes were always identical. In particular, whereas female flies had two identical-looking X chromosomes, in the male the X chromosome was paired with a Y chromosome, which looks different and is never present in the female. • Morgan deduced that a male must inherit the X chromosome from his mother and Y from his father, and he immediately spotted a correlation between these sex-linked chromosomes and the segregation of the factors determining eye color. When the mother was homozygous and had two copies of the gene for red eyes, the male offspring invariably had red eyes, even if the father had white eyes. But when the mother had white eyes, the male offspring did too, even if the fathers eyes were red. In contrast, a female fly gets one X chromosome from each parent, and if one passed along an X chromosome with a gene for red eyes, the offspring had red eyes because the color is dominant over white. Only when both parents gave her an X chromosome with a gene for white eyes did she display the recessive trait. From these observations, Morgan concluded that the allele-producing eye color must lie on the X chromosome that governs sex. This provided the first correlation between a specific trait and a specific chromosome.Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  37. 37. • Morgan’s experiments Experiment Gray body, Black body, vestigial long wings wings – Demonstrated the role × (wild type) of crossing over in GgLI Female ggll Male inheritance Offspring Gray long Black vestigial Gray vestigial Black long 965 944 206 185 Parental Recombinant phenotypes phenotypes 391 recombinants Recombination frequency = = 0.17 or 17% 2,300 total offspring Explanation G L g l GgLI ggll (female) (male) g l g l G L g l G l g L g l Eggs Sperm G L g l G l g L g l g l g l g l Offspring Figure 9.20 CCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  38. 38. Geneticists use crossover data to map genes • Morgan and his students – Used crossover data to map genes in DrosophilaCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  39. 39. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  40. 40. • Recombination frequencies – Can be used to map the relative positions of genes on chromosomes. Chromosome g c l Mutant phenotypes 17% 9% 9.5% Short Black Cinnabar Vestigial Brown aristae body eyes wings eyes Recombination (g) (c) (l) frequencies Long aristae Gray Red Normal Red (appendages body eyes wings eyes on head) (G) (C) (L) Wild-type phenotypesCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  41. 41. SEX CHROMOSOMES AND SEX-LINKED GENES Chromosomes determine sex in many species • In mammals, a male has one X chromosome and one Y chromosome – And a female has two X chromosomesCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  42. 42. • The Y chromosome – Has genes for the development of testes • The absence of a Y chromosome – Allows ovaries to developCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  43. 43. • Other systems of sex determination exist in other animals and plants 22 22 + + XX X Figure 9.22 B 76 76 + + ZW ZZ Figure 9.22 C 32 16 Figure 9.22 DCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  44. 44. Sex-linked genes exhibit a unique pattern of inheritance • All genes on the sex chromosomes – Are said to be sex-linked • In many organisms – The X chromosome carries many genes unrelated to sexCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  45. 45. • In Drosophila – White eye color is a sex-linked trait Figure 9.23 ACopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  46. 46. • The inheritance pattern of sex-linked genes – Is reflected in females and males Female Male Female Male Female Male XR X R × Xr Y X R Xr × XR Y XR X r × Xr Y Sperm Sperm Sperm Xr Y XR Y Xr Y Eggs XR X R Xr XR Y XR XR X R XR Y XR X R Xr XR Y Eggs Eggs R = red-eye allele Xr Xr X R Xr Y Xr Xr Xr Xr Y r = white-eye allele Figure 9.23 B Figure 9.23 C Figure 9.23 DCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  47. 47. Genetic Determination of Sex Creates Dosage Problems In mammals females have 2 X chromosomes, the males only 1 If nothing were done to compensate the females would get a double dose of any gene products from the X chromosome, compared to the dose that males get Nature solves this problem by shutting down one whole X chromosome in mammalian females • X chromosome inactivation is called Lyonization after Mary Lyon who discovered it • Inactive X chromosome appears in condensed state as a Barr body (p. 272, text) • Inactivation of X chromosomes in different cells is somewhat random The calico cat is a product of X chromosome inactivation • Genes for coat color of the cat are on the X chromosome • One gene produces a black color; its allele produces orange • To get a calico coat a cat must be heterozygous, with genes for both the orange and the black color • If the X chromosome with the black gene is inactivated that cell will produce orange • If the X chromosome with the orange gene is inactivated the cell will produce black • Inactivation occurs in patches, giving the orange and black coat of the calicoCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  48. 48. CONNECTION Sex-linked disorders affect mostly males • Most sex-linked human disorders – Are due to recessive alleles – Are mostly seen in males Queen Albert victoria Alice Louis Alexandra Czar Nicholas II of Russia Figure 9.24 A Figure 9.24 B AlexisCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  49. 49. There are about 1,098 human X-linked genes. Most of them code for something other than female anatomical traits. Many of the non-sex determining X-linked genes are responsible for abnormal conditions such as…HemophiliaDuchenne Muscular DystrophyFragile-X SyndromeSome High Blood PressureCongenital Night BlindnessG6PD DeficiencyRed-Green Color Blindness.Male Pattern BaldnessMechanism of PRO051 in the restoration of Dystrophin Expression through Exon Skipping.Normal muscle produces dystrophin, a critical protein, in response to signals encoded in a precise lockstep manner into mRNA. The mRNA is then translated into dystrophin protein. In the muscle of patients with Duchenne muscular dystrophy, mutations in the dystrophin gene lead to the loss of one or Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  50. 50. Mechanism of PRO051 in the Restoration of Dystrophin Expression through Exon Skipping. Normal muscle produces dystrophin, a critical protein, in response to signals encoded in a precise lockstep manner into mRNA. The mRNA is then translated into dystrophin protein. In the muscle of patients with Duchenne muscular dystrophy, mutations in the dystrophin gene lead to the loss of one or more exons. The mRNA splices together the remaining exons; however, the missing pieces lead to errors in translation (frame shift) and loss of production of the dystrophin protein. Intramuscular injection of a small modified DNA molecule can enter Duchenne-affected muscle through abnormal muscle membranes; then enters the nucleus and binds to the dystrophin mRNA. The modified DNA molecule allows the mRNA to skip over the affected exons, and restores the reading frame of the mRNA, for new production of dystrophin. The dystrophin that is produced is not normal but probably retains considerable function.Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
  51. 51. • A male receiving a single X-linked allele from his mother – Will have the disorder • A female – Has to receive the allele from both parents to be affectedCopyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

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