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Mendelian Patterns of Inheritance

Mendelian Patterns of Inheritance. Mono- and Di- Hybrid Crosses. Two black mice are bred together. Over the course of three years, the parents produce 330 brown mice and 810 black mice. What might explain the differences between your hypothesis and reality?. Lethal Genes.

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Mendelian Patterns of Inheritance

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  1. Mendelian Patterns of Inheritance Mono- and Di- Hybrid Crosses

  2. Two black mice are bred together. Over the course of three years, the parents produce 330 brown mice and 810 black mice. • What might explain the differences between your hypothesis and reality?

  3. Lethal Genes Some genes are lethal when both alleles are present. Lethality can occur before or after birth Huntington's disease in humans is caused by a lethal allele, death occurs later in life Other examples: Mouse coat color (yellow), Creeper legs in chickens, Manx Cats (no tails)

  4. An example is the "creeper" allele in chickens, which causes the legs to be short and stunted. Creeper is a dominant gene, heteroyzous chickens display the creeper phenotype If two creeper chickens are crossed, and 8 chicks are produced, describe (in an ideal world) the ratios of all surviving offspring…

  5. Manx Cats Cats possess a gene for producing a tail. The tailless Manx phenotype in cats is produced by a recessive allele that is lethal in its homozygous state. The allele interferes with normal spinal development, in heterozygous cats this results in lack of a tail. Show the cross between a manx cat and a normal cat. X

  6. X

  7. What are the gametes possible for an organism that is  AaBbRr? Mendel’s Three Laws 1. Dominance & Recessiveness 2. Segregation  3. Independent Assortment

  8. R = roundr = wrinkledY = yellowy = green

  9. Dihybrid Cross: RrYy x RrYy

  10. A Series of crosses……given the following F1offspring, what are:1. the P genotypes?2. expected percentages (or ratios) of F2? 100 % Aa

  11. If the parents from that cross had 100 babies… • How many round & yellow babies would we expect? • How many round & green babies would we expect? • How many wrinkled & yellow babies would we expect? • How many wrinkled & green babies would we expect? • How many degrees of freedom are there in this problem? • If there were the following 102 offspring, would we have to reject the hypothesis of the parent genotypes? • 58 round/yellow 19 round/green • 18 wrinkled/yellow 7 wrinkled/green

  12. Dragon Genetics

  13. In dragons, the allele for fire breathing is dominant.  Dragons can be fire breathers, or non fire breathers. Show the genotypes and phenotypes of all possible dragons.

  14. If a heterozygous fire-breathing dragon is crossed with one that does not breathe fire, how many offspring can you expect will be fire breathers?

  15. If two heterozygous dragons are crossed, how many offspring would you expect to NOT be fire-breathers?

  16. Also in dragons, wings are a dominant trait.  If you crossed two wingless dragons, how many of their offspring would you expect to have wings?

  17. Two winged dragons produce an offspring that does not have wings.  What are the genotypes of the parents?

  18. If a purebred winged dragon is crossed with a purebred wingless dragon, how many of their offspring will be expected to be winged and what is their genotype?

  19. Crosses that Involve 2 Traits

  20. A winged dragon (Gg) that breath fire (Ff) is crossed with one that is wingless and cannot breath fire. How many of their offspring will be winged fire breathers?

  21. A fire breathing winged dragon (GgFf) is crossed with one that is winged and cannot breath fire (Ggff) How many of the offspring do not have wings and cannot breath fire?

  22. So little Spyro has wings and can breath fire.  He does not know his genotype. Can Spyro find out his likely genotype?

  23. GregorMendel • Developed the fundamental laws of heredity  • He studied science and mathematics  • Blended Concept of Inheritance vs Particulate Theory of Inheritance  Mendel originally wanted to breed mice, but wasn't allowed to because it was considered scandalous

  24. 11.2 Mendel's Law of Segregation (MONOHYBRID CROSS)

  25. Review Terms F1  vs   F2 True Breeding vs Hybrid Self Pollination vs  Cross Pollination Homozygous vs Heterozygous

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