INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

The science of The science of inheritanceinheritance

Parents and Parents and offspringoffspring

heredity is the set heredity is the set of characteristics of characteristics an organism an organism receives from his receives from his parentsparents

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Gregor MendelGregor Mendel worked with peasworked with peas discovered 7 traits discovered 7 traits

in true breeding pea in true breeding pea plantsplants

F1 generationF1 generation F2 generationF2 generation

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

GeneGene functional unit that functional unit that controls inherited trait controls inherited trait expression that is passed expression that is passed on from one generation to on from one generation to the nextthe next Dominant alleleDominant allele a a

specific trait that appears specific trait that appears in the F1 generationin the F1 generation

Denoted with a capital Denoted with a capital letterletter

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Recessive alleleRecessive allele a a specific trait that is specific trait that is masked in the F1 masked in the F1 generationgeneration

Denoted with a Denoted with a small lettersmall letter

HomozygousHomozygous organism with two of organism with two of the same alleles for a the same alleles for a specific traitspecific trait

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

HeterozygousHeterozygous organism with two organism with two different alleles for a different alleles for a specific traitspecific trait

HybridHybrid organism organism heterozygous for a heterozygous for a specific traitspecific trait

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

SegregationSegregation A process that A process that

separates the separates the two allelestwo alleles

Independent Independent assortmentassortment

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Mendel’s principlesMendel’s principles individual units, called genes, individual units, called genes,

determine biological characteristicsdetermine biological characteristics For each gene, an organism For each gene, an organism

receives one allele from each receives one allele from each parent.parent.

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

if an organism inherits different alleles if an organism inherits different alleles for the same trait, one allele may be for the same trait, one allele may be dominant over the otherdominant over the other

some genes segregate independentlysome genes segregate independently

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

TURN AND TALKTURN AND TALK Expl n om n n E ai d i a ce Expl n om n n E ai d i a ces r t onE n neg ega i a d is r t onE n neg ega i a d i

p n nt ssortmde e de a ep n nt ssortmde e de a entEntE

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

MeiosisMeiosis ChromosomesChromosomes

Forming gametesForming gametes haploid and diploid cellshaploid and diploid cells

HaploidHaploid having one copy of having one copy of each chromosomeeach chromosome

DiploidDiploid having two copies of having two copies of each chromosomeeach chromosome

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Phases of meiosisPhases of meiosis Have students reproduce chart on pg Have students reproduce chart on pg

133 of book.133 of book. Meiosis and genetic diversityMeiosis and genetic diversity

chromosome combinations (pg 134 in chromosome combinations (pg 134 in book)book)

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Crossing overCrossing over exchange of exchange of chromosomal chromosomal segments between segments between a pair of a pair of homologous homologous chromosomes chromosomes during prophase Iduring prophase I

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

TURN AND TALKTURN AND TALK Expl n ow ross nai h c i Expl n ow ross nai h c i ov r n r s s g e i c ea e ge ov r n r s s g e i c ea e ge

n t v rs tEEe ic di e in t v rs tEEe ic di e i

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Analyzing Analyzing inheritance inheritance

ProbabilityProbability Probability and Probability and

geneticsgenetics

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

A closer look at heredityA closer look at heredity Incomplete Incomplete

dominancedominance complex complex heritance pattern in heritance pattern in which the which the heterozygous heterozygous phenotype is phenotype is intermediate between intermediate between two heterozygous two heterozygous parents parents

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Co-dominanceCo-dominance complex inheritance complex inheritance pattern that occurs pattern that occurs when neither allele when neither allele is dominant and is dominant and both alleles are both alleles are expressedexpressed

INTRODUCTION TO INTRODUCTION TO GENETICSGENETICS

Polygenic traitsPolygenic traits characteristic, characteristic, such as eye color such as eye color or skin color, that or skin color, that results from the results from the interaction of interaction of multiple gene pairsmultiple gene pairs