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Genetics and Heredity Part I: Intro and Vocab

Genetics and Heredity Part I: Intro and Vocab. What is heredity?. Heredity is the passing of traits from parent to offspring. Here are some traits or characteristics that are passed from parent to child:. eye color. cleft in the chin. length of eyelashes. widow’s peak.

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Genetics and Heredity Part I: Intro and Vocab

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  1. Genetics and HeredityPart I: Intro and Vocab

  2. What is heredity? Heredity is the passing of traits from parent to offspring. Here are some traits or characteristics that are passed from parent to child:

  3. eye color cleft in the chin

  4. length of eyelashes widow’s peak

  5. number and length of digits (fingers, toes)

  6. What is genetics? Genetics is the study of how traits are inherited through the pairing of alleles. An allele is a section of DNA code for one particular trait.

  7. A set of 2 alleles for the same trait is called a gene. Each gene is made up of 2 matching alleles per trait - one from your mom and one from your dad.

  8. Chromosomes are located in the cell’s nucleus. They are in pairs. They are made up of strands of DNA. DNA is a code or set of instructions. strand of DNA

  9. Pair of chromosomes (separated) One came from mom, the other from dad. Each stripe represents one allele. Each pair of stripes that are the same color represent one gene. Each color represents a different trait. mom dad

  10. One allele of each trait is passed on by the egg. The other allele for the same trait is passed on by the sperm. Freckles No freckles Black hair Blonde hair Blue eyes Brown eyes

  11. Alleles determine which traits you inherit from your parents. free hanging earlobe or attached earlobe Which allele did you inherit for each trait?

  12. left handed or right handed

  13. unable to curlable to curl or rollORor roll your tongueyour tongue

  14. History: Gregor Mendel Gregor Mendel was a monk, gardener, and scientist. Mendel was in charge of his monastery's vegetable garden. Austria, 1856

  15. Mendel bred and studied pea plants for many years.

  16. He observed and recorded the traits of pea plants and looked for patterns.

  17. The chart below shows the 7 traits Mendel kept track of. There are 2 alleles per trait.

  18. Mendel discovered that these traits were passed on from one generation to the next, or from parent to offspring. He is known as the “father of genetics.”

  19. How is one allele for a particular trait chosen over the other?

  20. Which eye color? + = My mom has blue eyes. My dad has browneyes. I have blue eyes, but my 3 sisters have brown eyes. WHY?

  21. There are 2 forms for each allele, a dominant allele and a recessive allele. When a dominant and a recessive allele pair up on a gene, the dominant allele masks the recessive allele.

  22. Here is a list of some common traits and their 2 alleles.

  23. In order to show the recessive trait, an organism must receive the recessive allele from both parents. + = Mom Dad Child #1 Child #2 Child #3 Blue eyes are a recessive trait. In order to have a blue-eyed child,both parents must have blue alleles. A person with blue eyes has2 alleles for blue eyes.

  24. The form of the trait you can actually see is called the phenotype. Medium skin tone, black hair, brown eyes, widow’s peak, no cleft chin, oval face, free earlobes, no dimples, no freckles When you describe a person, you are using the phenotype for each trait. Light skin tone, blonde hair, blue eyes, no widow’s peak, no cleft chin, round face, free earlobes, dimples, no freckles

  25. The two alleles that actually form the gene are called the genotype. Brown hair: Bb Blue eyes: ee Full lips: l l Attached earlobes: aa Face shape: HH

  26. Suppose the 2 red stripes on this chromosome represent the 2 alleles for the trait “eye color” for a girl named Sue. Dad’s genes Mom’s genes Sue’s right eye One allele came from her dad, the other from her mom. You can see that Sue’s eyes are brown, so herphenotypefor eye color is “brown”.

  27. If Sue inherited one allele for brown eyes from each parent, her genotype for eye color is “brown / brown” or BB. (homozygous genotype) If Sue inherited one allele for brown eyes and one allele for blue, her genotype for eye color is “brown / blue” or Bb. (heterozygous genotype) B B B b

  28. Can we predict a particular trait of future offspring? In other words, can I predict whether my son will have blue or brown eyes? Will write with his left or right hand? Will have a cleft chin or hitchhiker’s thumb? Yes, if you know each parent’s genotype for that trait. You use a Punnett square.

  29. What is a Punnett square? A Punnett square is a mathematical tool used to predictwhich traits will appear in the offspring of a particular set of parent organisms.

  30. Capital letters represent dominant traits. Lowercase letters represent recessive traits.

  31. Face Shape Oval: O Square: s Eye Color Brown: B Blue: b Praying Hands Left thumb on top: L Right thumb on top: r

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