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SEX-LINKED INHERITANCE

SEX-LINKED INHERITANCE. Objectives. Meet with Thomas Hunt Morgan Define Sex Linkage Define Sex linkage in Drasophila melaganester Describe Hemoplia , colourblidness and Muscular dystrophies. SO WHAT IS SEX LINKED INHERITANCE ??. Thomas Hunt Morgan.

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SEX-LINKED INHERITANCE

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  1. SEX-LINKED INHERITANCE

  2. Objectives • Meetwith Thomas Hunt Morgan • Define SexLinkage • Define Sexlinkage in Drasophilamelaganester • DescribeHemoplia, colourblidnessandMuscular dystrophies

  3. SO WHAT IS SEX LINKED INHERITANCE ??

  4. Thomas Hunt Morgan • He was an American evolutionary biologist , geneticist and embryologist • Drosophila became a major model organism with his studies • Morgan hypothesized that an allele for eye color is carried on the X chromosome • Sex linkage was discovered by Thomas Hunt Morgan

  5. Q1-In a cross between a white-eyed female fruit fly and red-eyed male, what percent of the female offspring will have white eyes? (White eyes are X-linked, recessive) • A. 100%B. 25% • C. 50% • D. 75% • E. 0%

  6. Sex linkage is a term that applied to genes located on sex chromosomes. • A trait that is controlled by a gene found on the sex chromosome is a sex- linked trait.

  7. Sex-Linked Inheritance In humans X-linkedinheritance Y-linkedinheritance X-linkedrecessive Xlinked dominant

  8. X-linkedrecessiveinheritance • X-linked inheritance means that the gene causing the trait or the disorder is located on the X chromosome • Recessive inheritance is when both matching genes must be abnormal to cause disease. • If only one gene in the pair is abnormal, the disease does not occur.

  9. X-linkedrecessiveinheritanceHemophlia Hemophilia is a rare bleeding disorder in which the blood doesn't clot normally. If you have hemophilia, you may bleed for a longer time than others after an injury.

  10. X-linkedrecessiveinheritanceColor-Blindness • Color-blindness is the inability to distinguish the differences between certain colors.. The picture on the rightis how people with blue yellow color blindness see things.

  11. Question 2: A human female "carrier" who is heterozygous for the recessive, sex-linked trait causing red-green color blindness (or alternatively, hemophilia), marries a normal male. What proportion of their male progeny will have red-green color blindness (or alternatively, will be hemophiliac)? A. 100% B. 75% C. 50% D. 25% E. 0%

  12. Q3:A human female "carrier" who is heterozygous for the recessive, sex-linked trait red color blindness, marries a normal male. What proportion of their female progeny will show the trait? A. All B. 1/2 C. 1/4 D. 0 E. 3/4

  13. X-linkedrecessiveinheritanceMuscular dystrophies Muscular dystrophy (MD) is a genetic disorderthat gradually weakens the body's muscles.

  14. Additionally, numerous genes whose expression yields enzymes are sex-linked. Glucose-6-phosphate dehydrogenase and hypoxanthine-guanine-phosphoribosyltransferase are two examples. In the latter case, the Lesch-Nyhan syndrome results from the mutant form of the X-linked gene product.

  15. X-linked dominantinheritance • Disorders generally seen in females • Lethal in males • X-linked dominant disorders are less common than X-linked recessive disorders

  16. Y-linkedinheritiance 1. excessively hairy 2-Ichthyosishystrix

  17. Resources • http://pennstatehershey.adam.com/content.aspx?productId=117&pid=2&gid=9882 • http://www.britannica.com/EBchecked/topic/537011/sex-linked-character • http://ocw.tufts.edu/Content/20/lecturenotes/301642/301646 • http://www.thereforyou.com/understanding-hemophilia/hemophilia-genetics/ • http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/ • http://www.color-blind.org/Blue-Yellow-Color-Blindness.php • http://www.biology.arizona.edu/mendelian_genetics/problem_sets/sex_linked_inheritance/07Q.html • Ted Ankara CollagesTeacher’sNotes in Biotedwebsite

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