Mendelian Genetics

simple genetics

what is Mendelian genetics also known as?

Gregor Mendel

-austrian monk
-father of genetics

Characteristic or Trait

the physical features that are inherited. They can occur in different versions.

characteristic, trait, version, trait

Face color is _________ or _____. White or not white is the _______ of the ____.

hybrid

offspring from a cross of parents with different or contrasting traits

Generation

a group of offspring from a given group of parents

Genetics

the study of heredity

Genetic cross

mating or breeding of two individual organisms

Self pollinate

fertilize itself

Cross pollinate

pollen of one plant is carried to the flower of another plant

monohybrid cross

a cross studying one pair of contrasting forms of a trait

True-breeding

plants or organisms that always produce the same type of offspring. Also called Pure bred.

Mendel’s explanations for the patterns of heredity in garden pea plants.

Modern genetics is based on

People thought that traits were blends from parents.

Before Mendel what did people believe about how we inherited traits?

-They have seven traits with two contrasting forms for each trait
-They usually self pollinate
-Grow easily

Why did Mendel choose pea plants to study?

Mendel allowed true-breeding plants for each trait to self fertilize and called these true or pure bred plants the parental or P generation.

Mendel’s First Experiments step 1:

parental or p generation

the first set of parents crossed

He then crossed two true breeding plants of the same character but with different forms of the trait.

Mendel’s First Experiments step 2:

first filial or F1 generation

the generation of hybrids produced from a cross between the genetically different individuals called parents

He then allowed the F1 generation to self fertilize and produce new plants. He called the offspring from this cross the second filial or F2 generation.

Mendel’s First Experiments step 3:

alleles

different versions of genes

dominant

the expressed allele( what showed up in the F1

recessive

the hidden allele(didn’t show up in the F1)

genotype

a specific combination of alleles in an individual.(the actual genetic makeup)

phenotype

the detectable trait or traits that result from the genotype of an individual(the observable form of the trait

The simple pattern of inheritance. In these patterns, two of several versions of a gene combine and result in one of several possible traits.

what does Mendelian theory explain

Mendel called the version that showed up the ________ trait and the one that was hidden the _________ trait

Law of dominance

that the dominant allele is the one that showed up in the F1 generation

Law of independent assortment

during gamete formation the alleles of each gene segregate independently.

phenotype

The physical trait or the observable form of the trait

genotypes

are the genes that code for these traits

capital, lower case

We use a ______ letter to represent the dominant gene and a ________ letter to represent the recessive gene

pure bred

said to be Homozygous for the trait.

hybrid

said to be Heterozygous for the trait.

homozygous

an individual that carries two identical alleles of a gene

heterozygous

individual that carries two different alleles of a gene

gene

unit of heredity; part of the DNA that codes for a particular protein

Dihybrid crosses

When you cross two traits at a time

Incomplete Dominance

The heterozygote shows an inbetween or blend of the two homozygous phenotypes
Red x white = pink
Black x white= gray
Long x short =medium

Co dominance

the heterozygote shows both homozygous phenotypes.
Red x white= red/white

Phenotypes: Genotypes:
Type A IA IA or IA i
Type B IB IB or IB i
Type O ii
Type AB IA IB

human blood type

type AB

blood is an example of codominance

multiple alleles

Human blood type shows

mutiple alleles

More than the normal two alleles for a trait

2

Each organism can only have _____ of the alleles for that trait to be expressed

polygenic traits

Traits that have more than one pair of genes involved in their expression
-hair color
-eye color
-skin color