Reproduction and Genetics

Two Types of Reproduction

• _________________- Only one parent and genetic material is identical to parent.

• __________________- Two parents and offspring receives genes from both parents.

Asexual Reproduction

Sexual Reproduction

Asexual ReproductionBinary Fission- asexual reproduction that occurs

in single celled organisms in which genetic material is copied and one cell divides into two identical daughter cells. EX: Bacteria reproduce this way, and Yeast

Asexual ReproductionBudding- an organism grows a part of of its

main body and this new growth eventually breaks off to become a new organism. Ex: Hydra (simple animal similar to jelly fish)

Asexual ReproductionFragmentation- Fragmentation is a form of asexual

reproduction where a new organism grows from a fragment of the parent. Each fragment develops into a mature, fully grown individual. Ex: Starfish, and some fungi.

Sexual Reproduction• Sexual Reproduction- Type of reproduction in

which male and female reproductive cells combine to form new offspring with genetic material from both parents.

***Offspring has genetic material from each parent which creates- Offspring is NOT identical to parent!

Sexual Reproduction - Variation

23 Chromosomes 23

Chromosomes

46 Chromosomes

Male Gamete Female Gamete

Sexual Reproduction - Variation

23 Chromosomes 23

Chromosomes

46 Chromosomes

Male Gamete Female Gamete

Asexual Reproduction Sexual Reproduction

Disadvantages

Advantages

Selective Breeding

• When humans select organisms for breeding to get desirable traits.

Breeding chickens that lay the most eggs

1. Gregor Mendel – was an Austrian monk born in 1822 who is known as the “father of genetics”

Genetics – the scientific study of heredity

Heredity – the passing of traits from parents to offspring

a. Traits are inherited by parents passing alleles to their offspring (1 allele from dad & 1 allele from mom)

a. Allele= different forms of the same gene (ex: eye color = gene; brown eyes= allele, blue eyes= allele

b. Some alleles are dominant (R) and some are recessive (r)

• Dominant – will always express its form of a trait when present

• Recessive – will only express its form of a trait when the dominant allele is not present.

Genotypes• Homozygous (rr, RR) SAME ALLELES• Heterozygous (Rr) – dominant trait always shows.

DIFFERENT ALLELES

Remember: DNA is found in the nucleus. It is organized into a chromosome before it is copied.

Genes are located on chromosomes!!

Sex cells (gametes) are produced by meiosis and have half the number of chromosomes (haploid)

For every Gene or trait, an individual gets ____ alleles2

Alleles

____________ alleles are represented by a capital letter and are expressed even if one is present in the genotype.

(Ex: BB= brown eyes, Bb= brown eyes)

___________ alleles are represented by a lower case letter, and are only expressed if the dominant allele in not present. (Ex: bb= blue eyes)

DOMINANT

RECESSIVE

Vocabulary

______________is the combination of alleles

_______________ is the trait that is expressed

BB bb Bb

Brown eyes Blue Eyes

Genotype

Phenotype

Give the name of the Genotype

If both alleles are dominant (BB), we call this ____________Homozygous Dominant

The phenotype will be _____________________Brown Eyes

If both alleles are recessive (bb), we call this _________________Homozygous Recessive

The phenotype will be ________________Blue Eyes

If one allele is dominant and the other is recessive (Bb), we call this __________Heterozygous

The phenotype will be _________________Brown Eyes

Name the Genotype

Bb=

bb=

BB=

Heterozygous

Homozygous Recessive

Homozygous Dominant

Give me the genotype or genotypes possible for the

following phenotypesBrown Eyes =

Blue Eyes =

BB or Bb

bb

Brown eyes (B) is dominant to blue eyes (b)

Cross a heterozygous brown eyed man with a blue eyed woman.

________ X ________B b b b

B b

b

b

B b bb

Bb bb

Phenotypic Ratio __________

Genotypic Ratio ____________

2 : 2

2 : 2

Brown eyes (B) is dominant to blue eyes (b)

Cross a heterozygous brown eyed man with a blue eyed woman.

________ X ________B b Bb

B b

B

b

B B Bb

Bb bb

Phenotypic Ratio __________

Genotypic Ratio ____________

1:2:1

3:1