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Sex-linked Traits

Sex-linked Traits. Using punnett squares. INHERITANCE OF SEX CHROMOSOMES. Humans have 23 pairs of chromosomes. Autosomes: 22 pairs are non-sex determining chromosomes. the 23rd pair determines the sex of the offspring. female sex chromosomes - XX. male sex chromosomes - XY.

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Sex-linked Traits

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  1. Sex-linked Traits Using punnett squares

  2. INHERITANCE OF SEX CHROMOSOMES Humans have 23 pairs of chromosomes Autosomes: 22 pairs are non-sex determining chromosomes the 23rd pair determines the sex of the offspring

  3. female sex chromosomes - XX

  4. male sex chromosomes - XY ( y is smaller than x and has different genes)

  5. Who determines the child's sex? the male

  6. SEX- LINKED TRAITS an inherited trait that has a gene on the x chromosome but no corresponding gene on the y chromosome (genes that only exist only on the sex chromosomes)

  7. Examples of human sex-linked traits • Hemophilia • Red-green color blindness • Muscular dystrophy • Male pattern baldness

  8. How to work sex-linked trait problems Hemophilia: is a rare, inherited bleeding disorder in which your blood doesn’t clot normally. If you have hemophilia, you may bleed for a longer time than others after an injury. You also may bleed internally, especially in your knees, ankles, and elbows. This bleeding can damage your organs or tissues and, sometimes, be fatal.

  9. All possible genotypes & phenotypes: genotypes phenotypes Normal female Female carrier Female hemophiliac Normal male Male hemophiliac XHXH XHXh XhXh XHY XhY

  10. What is a carrier? carrier - expresses the normal characteristic but has both dominant and recessive genes (have the gene for a trait but do not express the trait themselves) XHXh for sex-linked traits, males cannot be carriers

  11. How to work sex-linked trait problems:start with this type of punnett square X X X X X X X Y X Y X Y

  12. How to work sex-linked trait problems:put the genes on the X chromosome H h X X H H H H h X X X X X H h Y X Y X Y Cross a normal husband with a carrier wife

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