1

UNDERSTANDING HEREDITY

GENETICS AND MUTATIONS

2

GeneticsPart One

3

Genetics is…

OThe scientific study of heredity

4

A gene is…

OA sequence of DNA that codes for a protein and determines traits

5

What is an allele?

OOne of two or more alternative forms of a gene that are found at the same place on a chromosome.

6

What does the term heterozygous mean?

OThe organism has two different alleles for a trait.

OExample: Tt Bb

7

What does the term homozygous mean?

OThe organism has two of the same alleles for a trait.

OExample: TT or tt BB or bb

8

OComplete section determining heterozygous or homozygous genotypes

9

What is a genotype?

OThe actual genetic makeup of an organism.

10

What is a phenotype?

OThe physical characteristics of an organism.

11

OComplete section on phenotype/genotype

12

Who was Gregor Mendel?

OThe “Father” of genetics

13

What was his contribution?

OHis experiments laid the foundation of the science of genetics.

OHe noticed that traits could disappear in one generation and reappear in later generations.

14

Gregol MendelBorn July 20, 1822

Heinzendorf bei Odrau, Austrian Empire

(now Hynčice, Czech Republic)

Died January 6, 1884 (aged 61)

Brno (Brünn), Austria-Hungary (now Czech Republic)

Nationality Empire of Austria-Hungary

Fields Genetics

Institutions St Thomas's Abbey

Alma mater University of Olomouc

University of Vienna

Known for Creating the science of genetics

Click icon to add picture

15

OComplete section on monohybrid crosses

ONow start “Practice with Crosses”

16

GeneticsPart Two

17

Define Independent Assortment

OIndependent segregation of genes during the formation of gametes.

ORemember: Meiosis is the formation of gametes.

18

Define Law of Segregation

OSeparation of alleles during gamete formation.

OExample: 1 of 2 alleles for eye color will go to each sperm or egg

19

Define Co-dominant

OBoth alleles of a gene contribute to the phenotype

OExamples: Type AB blood; 1 blue eye and one green eye; speckled chickens

20

Define Incomplete Dominance

OOne allele cannot dominate another; the final phenotype is a blend of the 2 alleles

OExample: cross a red carnation with a white carnation makes a pink carnation

21

Co-dominance Incomplete Dominance

22

ORedefine genotype and phenotype

23

Co-DominanceHow many

genotypes are there?

How many phenotypes are

there?

OThree: AA,BB, AB

OThree

24

OComplete examples of incomplete dominance.

25

Incomplete dominanceHow many

genotypes are there?

How many phenotypes are

there?

OThree: RR-red rr-white Rr-pink

OThree

26

OComplete examples of co-dominance.

27

GeneticsPart Three

28

Sex chromosomesWhat are the female sex

chromosomes?What are the male sex chromosomes?

OXX OXY

29

What does it mean for a trait to be sex-linked?

OIt is carried on one of the sex chromosomes, most likely the X

30

Examples of sex-linked traits would be…

OThe ability to see color (color blindness)

OHaving a full head of hair (baldness)

OBlood clotting properly (hemophilia)

31

32

What is a di-hybrid cross?

OA cross between two individuals with two different traits that you are studying

OComplete examples and problems

33

Mutations

34

What is a mutation?

OGenes code for…

OMutations are…

OProteins

OMistakes in genetic code that affect the final protein

35

What is a point mutation?

Click icon to add picture

A mistake in one nitrogen base of an

mRNA codon

36

Types of point mutations:

O Substitution – 1 nucleotide is switched for another

Example: CAT GCA CAT GCGO Insertion or deletion – 1 nucleotide is

inserted/deleted in sequence Example: CAT GCA CAT GAC A Example: CAT GCA CAT CA

37

Effects of point mutations

O Substitution

O Insertions/deletions

O Might have no effect on/or will only effect one amino acid

O Change how the sequence is read – called a frameshift mutation

38epidermolysis bullosa 

39

What is a chromosomal

mutation?

Click icon to add picture

A change in the number or structure of

chromosomes.

40

Types of chromosomal mutations

ODeletion - entire gene(s) deleted

ODuplication – an extra copy of gene(s) added

O Inversion – segment of chromosome is flipped over and reversed in place

OTranslocation – segment of chromosome breaks off/relocates to another

41

Can be the result of:Inversion, deletion or translocation

Result of:Duplication

42

When mutations go…

Wrong Right

ODisruption of biological activities

ODisabilityODeath

OSource of genetic variation

OMay allow some members of a species a better chance to survive

43