Monohybrid Crosses

• What does monohybrid inheritance examine?

  Alleles for a single gene inheritance
• How are predictions about offspring phenotypes made in monohybrid crosses?

  Using genotypes, phenotypes, and meiosis

  
• What is the chance of inheriting either allele from parents in a monohybrid cross?

  Equal chance for both alleles
• What is the purpose of genetic diagrams in predicting inheritance?

  To present information clearly for predictions
• What is a Punnett square used for?

  To predict offspring genotypes and phenotypes

  
• Why can real-life results differ from predictions in genetic diagrams?

  Because results are based on chance

  
• What are the two alleles for horse coat color mentioned?

  B (black) and b (chestnut)

  
• What does the allele B produce in horses?

  Black coat when present
• What does the allele b produce in horses?

  Chestnut coat in homozygous individuals

  
• What is the predicted ratio of phenotypes in the offspring of the horse coat color cross?

  3 black coat : 1 chestnut coat

  
• What is the predicted ratio of genotypes in the offspring of the horse coat color cross?

  1 BB : 2 Bb : 1 bb
• How many alleles can a diploid individual inherit for a gene?

  Two alleles
• What are the three alleles for human blood groups?

  I^A, I^B, and i
• What do the alleles I^A and I^B produce in blood?

  Antigen A and antigen B respectively
• What does the allele i produce in blood?

  No antigens produced in the blood
• What are the predicted ratios of phenotypes in the offspring of a blood type A and B cross?

  1 AB : 1 A : 1 B : 1 O

  
• What are the predicted ratios of genotypes in the offspring of a blood type A and B cross?

  1 I^A I^B : 1 I^A i : 1 I^B i : 1 ii
• What is the process for constructing genetic diagrams?

  • Identify parental phenotypes and genotypes
  • Determine possible gametes from each parent
  • Create a Punnett square
  • Calculate predicted ratios of phenotypes and genotypes

  
• What is codominance in genetics?

  • Both alleles are expressed equally
  • Results in multiple phenotypes
  • Represented with capital letters and superscripts
• What are the key differences between monohybrid crosses and multiple alleles?

  • Monohybrid crosses involve one gene
  • Multiple alleles involve more than two alleles
  • Both can use Punnett squares for predictions