Chapter 3 - Mendelian Inheritance

Blending theory

Theory that factors that control hereditary traits are maleable; traits can blend together generation after generation

Mendel

The blending theory was refuted by ____’s experiments

homozygous, discontinuous

Mendel was successful because he…

• Chose a very suitable organism

• Took time to ensure pure breeding (same alleles and thus ____)

• Concentrated on one or a few ____ characters at a time

  • Adopted quantitative form of analysis

Cross-fertilization and self-fertilization

What are the two types of fertilization that Mendel used in his experimental system?

Cross-fertilization

Type of fertilization where pollen and egg are derived from different plants

Self-fertilization

Type of fertilization where pollen and egg are derived from the same plant

Parental generation

Pure bred lines

First filial generation

Offspring of cross-fertilization of parentals

Second filial generation

Offspring of self-fertilization of F₁ plants

Third filial generation

Offspring of self-fertilization of F₂ plants

Same

When Mendel performed a reciprocal cross where dwarf plants were pollinated using pollen from tall plants, were the results the same or different?

For all seven traits that Mendel studied…

• The F₁ generation showed ____ of the two parental traits

• The F₂ generation showed an ~____ ratio of the two parental traits

• Reciprocal crosses yielded ____ results

Alleles

Hereditary factors which consist of one from each parent

dominant, recessive

When the two factors of a single trait are different, one is ____ and its effect can be seen, while the other is ____

homozygous, heterozygous

If an organism’s alleles are identical, the organism is ____; if the alleles are different, then the organism is ____

Genotype

Specific allelic composition of an individual

Phenotype

Physical appearance of an individual

Environment

Phenotype is a product of the genotype and what?

Law of independent assortment

Law that states that during gamete formation, the segregation of any pair of hereditary determinants is independent of the segregation of other pairs (ex. eye color and blood type)

9:3:3:1

If genes assort independently, what will the predicted phenotypic ratio be?

Loss of function alleles

Defective copies of genes

2, 3, 2, 1/4

If n=# of heterozygous pairs involved…

• The number of possible parental gametes is __ⁿ

• The number of different genotypes in zygotes is __ⁿ

• The number of different phenotypes in zygotes is __ⁿ

• The proportion of homozygous recessive in F₂ is __ⁿ

Product rule

The probability of the occurrence of independent events is the product of their respective probabilities; “and” rule

Sum rule

The probability of the occurrence of one of several mutually exclusive events is the sum of their respective probabilities

If the two events are not mutually exclusive, then…

P(A or B) = P(A) + P(B) - [P(A) x P(B)]

Binomial expansion

The probability of unordered mutually exclusive events is defined by the binomial theorem