Lesson #16 Inheritance of Genetic Information #1

• What is the primary organism used in Mendelian genetics experiments?

  Pea plants
• Why are pea plants considered suitable for genetic experiments?

  They have multiple traits and are easy to grow
• What are the two methods of fertilization in pea plants?

  Cross-fertilization and self-fertilization
• What are the generations involved in a monohybrid cross?

  • Parent Generation: True breeding
  • F1 Generation: Shows dominant trait
  • F2 Generation: ¾ dominant phenotype, ¼ recessive form

  
• What is the F2 generation ratio in a monohybrid cross?

  ¾ dominant phenotype and ¼ recessive form

  
• What is the actual ratio of the F3 generation in a monohybrid cross?

  1. 2:1 ratio

  
• What does homozygous mean in genetics?

  Having two of the same alleles
• What is the definition of genotype?

  Total set of alleles an individual contains
• What does phenotype refer to in genetics?


  Physical appearance of an individual
• What is the principle of segregation in genetics?

  Each individual receives one copy of a gene from each parent
• What did Mendel not know about during his experiments?

  Chromosomes or meiosis
• What does a Punnett square represent in genetics?

  The possible genetic combinations from a cross

  
• What does the letter P represent in a Punnett square?

  The dominant allele

  
• What is the result of a Pp x Pp cross in terms of flower color?

  Produces 1 homozygous white, 1 homozygous purple, and 2 heterozygous purple flowering plants

  
• What is the principle of independent assortment in dihybrid crosses?

  • Alleles assort independently
  • Segregation of allele pairs is independent
  • Independent alignment during metaphase 1 leads to independent segregation in gametes

  
• What shape represents a biological female in a pedigree chart?

  Circle
• What shape represents a biological male in a pedigree chart?

  Square
• What does a shaded region in a pedigree chart indicate?

  Individuals who are affected by the trait
• Can affected individuals in a dominant pedigree be heterozygous?

  Yes, affected individuals can be heterozygous
• What does a double horizontal line in a pedigree chart signify?

  Mating between related individuals
• What is a characteristic of recessive pedigrees?

  Affected individuals can be born to unaffected parents
• What are the key assumptions of Mendel's model of inheritance?

  • Each trait is controlled by 1 gene
  • Each gene has only 2 alleles
  • Clear dominant-recessive relationship between alleles
• What are multiple alleles in genetics?

  More than 2 alleles for a gene in a population
• What is an example of multiple alleles in humans?

  ABO blood type

  
• What are the three alleles involved in ABO blood typing?

  I$A$, I$B$, and i

  
• What does the i allele represent in ABO blood typing?

  Recessive allele with no surface antigens present

  
• What does the R allele represent in Rh blood typing?

  Rh antigen present
• What is polygenic inheritance?

  • Phenotype is accumulation of contributions by multiple genes
  • Traits show continuous variation, termed quantitative traits

  
• What is pleiotropy in genetics?

  One gene impacts multiple phenotypes
• What is an example of pleiotropy?

  Cystic fibrosis
• What is the difference between incomplete dominance and codominance?

  Incomplete dominance shows an intermediate phenotype, while codominance shows aspects of both phenotypes
• What is an example of incomplete dominance?

  Red flowers x white flowers = pink flowers
• What is epistasis in genetics?

  When one gene affects the expression of another gene
• How does epistasis affect Labrador retrievers' coat color?

  The E gene determines color distribution, affecting the expression of the B gene
• What phenotypic ratio is produced in Labrador retrievers due to epistasis?

  1. 3:4 ratio
• How does the environment influence phenotype?

  Environmental factors can affect physical traits
• What is an example of environmental influence on phenotype?

  Coat color in Siamese cats