Introduction to Genetics

11.1 – The Work of Gregor Mendel

Mendel’s Experiments

• Peas are a “________________________________.”

• Started with “_______________________________________________” plants

• ____________________: specific characteristic (e.g., seed color, plant height) of an individual

• ____________________: created from cross of true-breeding individuals

Pollination and Fertilization in Plants

How does pollination occur?_______________________________________________________

Cross-Pollination

How does cross-pollination increase genetic diversity?__________________________________

Pea Characteristics

Dominant and Recessive Traits

The F1 Generation

Mendel’s F1 Crosses

When Mendel crossed plants with ____________________________ traits, the _____________ offspring showed traits of only ________________ parent.

Yellow seed color is _________________ to green seed color

Green seed color is_____________________________ yellow seed color.

The F2 Generation

Genes and Alleles

• ________________________________: passed from one generation to the next; determine an individual’s characteristics

• _____________________________: the different forms of a gene

Principle of Dominance

• Some alleles are _____________________, some ___________________________.

• An organism with at least ________________________ dominant allele will _______________ that trait.

• An organism with a ________________________ allele will exhibit the trait __________ in the ____________________ of a dominant allele.

What proportion of F2 offspring were short?

________________

What proportion of F2 offspring were tall?

________________

Characteristics such as seed color

are determined by_____________________.

Yellow and green seed colors are

determined by _______________________.

The allele for yellow seeds is _____________to the allele for green.

Segregation

________________________________: separation of alleles during gamete formation

The Formation of Gametes

Introduction to Genetics

11.2 – Applying Mendel’s Principles

Determining Probability

_____________________________: the likelihood an event will occur

• Probability of either outcome:

• Three coin tosses?

• Each flip is an independent event.

Using Segregation to Predict Outcomes

Genotype and Phenotype

______________________: genetic makeup ___________________________: physical traits

Two organisms may share the same________________________________.

but have different___________________________.

Probability of a gamete receiving a T?__________________

Probability of gamete receiving a t? ___________________

Probability of tall offspring is_________________________

Probability of short offspring is _______________________

Heterozygous and Homozygous

__________________________: has two identical alleles for a gene

__________________________: has two different alleles for a gene

Which are:

homozygous? ________________________________

heterozygous? _______________________________

Making a Punnett Square

Making a Punnett Square: Two Factors

The Two-Factor Cross: F1

The Two-Factor Cross: F2 I

_______________________________________: Genes for different traits can ____________________ independently during ________________________________ formation.

Summary of Mendel’s Principles, Part I

Inheritance is determined by units called__________________________ , which are passed from parents to offspring.

Where more than one form of a gene for a single trait exists, some alleles may be__________________________ and others_________________________________.

Summary Mendel’s Principles, Part II

Each adult has two copies of each gene—one from each parent. These genes _____________________________ from each other when gametes are formed.

Alleles for different genes usually segregate______________________________ of each other.

Introduction to Genetics

11.3 – Other Patterns of Inheritance

Incomplete Dominance

• Some alleles are neither __________________ nor _______________________.

• ____________________________: One allele is not completely dominant over another.

Codominance

• The phenotypes for ___________________________ alleles are clearly expressed.

• Examples: chicken _____________________ color, human protein controlling __________________ cholesterol levels

Multiple Alleles

• Many genes exist in more than _____________________ forms.

• Examples: _______________________________________________, fur color in rabbits

Polygenic Traits

• Many traits are produced by the _________________________ of ______________ genes.

• Examples: ______________________ in fruit flies, ________________________ in dogs

• Traits typically show a _______________________________________ of phenotypes.

Genes and the Environment

_______________________ conditions can affect gene expression and influence genetically determined traits.

The ___________________________of an organism is only partly determined by its____________________________ .

Introduction to Genetics

11.4 – Meiosis

Chromosome Number

_____________________________________: chromosomes with the same genes, one originally from each of the organism’s parents

____________________: containing both sets of homologous chromosomes; 2N

______________________: containing only a single set of chromosomes; 1N

Reviewing Mitosis

Meiosis

Prophase I

Metaphase I

Anaphase I

Telophase I

Prophase II

Metaphase II and Anaphase II

Telophase II and Cytokinesis

The end product of meiosis is__________________________ daughter cells that have_______________________ the normal chromosome number.

Comparing Mitosis and Meiosis

Gene Linkage

___________________________ of different genes tend to be inherited __________________________ when those genes are located on the _________________ chromosome.

Gene Maps