DNA Part 2 - #64

• What is the focus of today's video?

  Different genetic terms and concepts
• What is an allele?

  A different version of the same gene
• What is the difference between dominant and recessive alleles?

  Dominant alleles are expressed over recessive ones
• What does homozygous mean?

  Having two identical alleles for a gene
• What does heterozygous mean?

  Having two different alleles for a gene
• What is a genotype?

  The entire collection of alleles an organism has
• What is a phenotype?

  The observable characteristics from a genotype
• If a mouse is heterozygous for fur color with one allele for purple and one for green, what color will it be if purple is dominant?

  It will be purple
• What must be true for a mouse to be green?

  It must be homozygous recessive for green fur
• How does the expression of alleles work in a heterozygous mouse?

  Only the dominant allele is expressed
• How do the genotypes of the three mice differ?

  They have different alleles and genetic codes
• Why do the heterozygous and homozygous dominant mice have the same phenotype?

  Both express the dominant purple color
• What is the phenotype of the homozygous recessive mouse?

  It is green
• What are the key terms related to genetics discussed in the video?

  • Allele
  • Dominant
  • Recessive
  • Homozygous
  • Heterozygous
  • Genotype
  • Phenotype
• What is the relationship between genes and traits?

  • Genes are segments of DNA
  • Genes code for proteins
  • Traits are determined by genes
  • Traits can be influenced by multiple genes
• How do multiple alleles affect traits?

  • Different alleles can produce variations
  • Dominant alleles mask recessive ones
  • Traits can be influenced by interactions of several genes