Incomplete Dominance and Codominance (Non- Mendelian Genetics)

Learning Science Channel
8 Oct 202008:44

Summary

TLDRThe Learning Science Channel's video delves into Mendelian inheritance patterns, focusing on incomplete dominance and co-dominance. In incomplete dominance, heterozygotes display an intermediate phenotype between homozygous parents, as exemplified by the red and white flowered goumamela plants producing pink offspring. Co-dominance, on the other hand, shows both parental traits in the offspring, like the red and white haired cattle resulting in a roan calf. The video uses Punnett squares to illustrate these concepts, emphasizing the importance of understanding non-Mendelian inheritance patterns in genetics.

Takeaways

  • 🌟 Welcome to the Learning Science Channel, where educational videos on various scientific concepts are provided.
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  • 🧬 Today's lesson focuses on incomplete dominance and co-dominance, two patterns that deviate from Mendelian inheritance principles.
  • 🌺 Incomplete dominance occurs when a heterozygote displays a phenotype intermediate between two homozygous phenotypes, with no allele being completely dominant.
  • 🌸 An example of incomplete dominance is the cross between red and white flowered goumamela plants, resulting in pink-flowered offspring.
  • 📊 Using a Punnett square, the genotypic and phenotypic ratios for incomplete dominance can be determined, often resulting in a 1:2:1 ratio.
  • 🐄 Co-dominance is another non-Mendelian pattern where both alleles are expressed equally in the heterozygote, as seen in the red and white haired cattle cross.
  • 🔍 The resulting offspring in co-dominance exhibits a phenotype that combines traits from both parents, such as a roan cattle with red and white hairs.
  • 📚 Remember that in co-dominance, the phenotype of the heterozygote reflects both alleles, unlike typical dominance where one allele masks the other.
  • 📝 The video concludes with a question to test the viewer's understanding of incomplete dominance in puppies, encouraging active participation and engagement.

Q & A

  • What is the main focus of the Learning Science Channel's video?

    -The main focus of the video is to study incomplete dominance and co-dominance in the Mendelian patterns of inheritance.

  • What happens when the recessive gene is not observed in the presence of a dominant gene?

    -The effects of the recessive gene are masked when the dominant gene is present, following Mendelian principles of heredity.

  • What is incomplete dominance and how does it differ from the Mendelian pattern of inheritance?

    -Incomplete dominance is a non-Mendelian pattern of inheritance where a heterozygote shows a phenotype intermediate between the two homozygous phenotypes, with neither allele being completely dominant over the other.

  • Can you provide an example of incomplete dominance from the video?

    -An example of incomplete dominance is the cross between a red-flowered and a white-flowered goumamela plant, resulting in a pink-flowered goumamela plant.

  • How is the phenotype of the offspring from a cross between two pink goumamela plants described in the video?

    -The phenotypes of the offspring are red, pink, and white flowered goumamela plants, with a phenotypic ratio of 1:2:1 and a genotypic ratio of 1:2:1.

  • What is co-dominance and how does it manifest in inheritance?

    -Co-dominance is a non-Mendelian pattern of inheritance where both alleles are expressed equally in the phenotype of the heterozygote, resulting in offspring that exhibit traits of both parents.

  • Give an example of co-dominance mentioned in the video.

    -An example of co-dominance is when a red-haired cattle is crossed with a white-haired cattle, resulting in a roan cattle with red and white hairs.

  • How are the phenotypic and genotypic percentages calculated in the case of co-dominance with the roan cattle example?

    -In the case of co-dominance with the roan cattle, the phenotypic percentage is 100% roan cattle, and the genotypic percentage is 100% RW.

  • What is the phenotypic ratio when a roan cattle is mated with a white cattle, as per the video?

    -The phenotypic ratio when a roan cattle is mated with a white cattle is 2 roan cattle to 2 white cattle.

  • What is the significance of the Punnett square in understanding incomplete dominance and co-dominance?

    -The Punnett square is used to predict the genotypes and phenotypes of the offspring in crosses involving incomplete dominance and co-dominance, helping to visualize the inheritance patterns.

  • How does the video conclude in terms of learning outcomes?

    -The video concludes by encouraging viewers to apply their understanding of incomplete dominance and co-dominance to answer a question about puppy inheritance patterns.

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相关标签
GeneticsInheritanceMendelianIncomplete DominanceCo-DominanceBiologyEducationalScience ChannelHeredityGenetic Traits
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