Homework 3 is due 1115 Bonus 2 is

• Homework #3 is due 11/15 • Bonus #2 is posted • Today: Meiosis, producing genetically diverse offspring, and inheritance

{Meiosis: producing gametes} For life to exist, the information (genes) must be passed on. {Mitosis: producing more cells}

Gene for growth hormone Gene for brown hair pigment Gene for blue eye pigment Gene for hemoglobin similar to Fig 2. 18 Gene for DNA polymerase Haploid chromosomes

Allele for low express (short) Gene for growth hormone Allele for high express (tall) similar to Fig 2. 18 Allele for black hair Gene for hair color Allele for black hair Allele for sickle cell Hb Gene for hemoglobin Allele for normal Hb Diploid chromosomes

Each pair of chromosomes is comprised of a paternal and maternal chromosome

Meiosis splits apart the pairs of chromosomes. Fig 2. 19 X 23 in humans

haploid X 23 in humans diploid X 23 in humans Inheritance = The interaction between genes inherited from Mom and Dad.

Asexaul Reproduction extremely low genetic diversity vs. Sexaul Reproduction greater genetic diversity How does sexual reproduction generate genetic diversity?

sister chromatids= replicated DNA (chromosomes) tetrad= pair of sister chromatids Fig 2. 41

Meiosis splits apart the pairs of chromosomes. Fig 2. 19 X 23 in humans

Fig 4. 3 Crossing-over (aka Recombination) DNA cut and religated

Crossing-over: Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes. Fig 4. 5

Crossing-over: Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes. Fig 4. 4

Crossing-over: Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes. Fig 4. 5

Asexaul Reproduction extremely low genetic diversity vs. Sexaul Reproduction greater genetic diversity How does sexual reproduction generate genetic diversity?

Independent Assortment (aka Random Assortment) Fig 3. 8

Independent Assortment 2 possibilities for each pair, for 2 pairs 22 = 4 combinations Fig 3. 8

Independent Assortment 2 possibilities for each pair, for 23 pairs 223 = 8, 388, 608 combinations Fig 3. 8

Box 2. 2 Crossingover Meiosis: In humans, crossing -over and (Ind. Assort. ) independent assortment lead to over 1 trillion possible unique gametes. (1, 000, 000) Meiosis II 4 Haploid cells, each unique

Box 2. 2

Box 2. 2 4 haploid cells

{Producing gametes} Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes. {Producing more cells}

haploid X 23 in humans diploid X 23 in humans Inheritance = The interaction between genes inherited from Mom and Dad.

Do parents’ genes/traits blend together in offspring? Fig 6. 4

In many instances there is a unique pattern of inheritance. Traits disappear and reappear in new ratios. Fig 2. 12

Genotype Pg 23 Phenotype

Human blood types Pg 225

One gene with three alleles controls carbohydrates that are found on Red Blood Cell membranes A A A RBC A A Allele A = A carbs B B B RBC B B B Allele B = B carbs Allele O = no carbs

Human blood types

We each have two versions of each gene… A So A A RBC A A Genotype could be A and A OR A and O

Recessive alleles do not show their phenotype when a dominant allele is present. A A A RBC A A Genotype could be A and A OR A and O

What about… RBC Genotype = ? ?

What about… RBC Genotype = OO

What about… B A A B A RBC B A B B A

What about… B A A B A RBC B A B Genotype = AB B A

Human blood types AA or AO BB or BO AB OO

If Frank has B blood type, his Dad has A blood type, And his Mom has B blood type… Should Frank be worried?

Mom=B blood possible BB or BO genotypes Dad=A blood AA or AO

possible genotypes Mom=B blood Dad=A blood BB or BO AA or AO Gametes all B / 50% B and all A / 50% A and 50% O

possible genotypes Mom=B blood Dad=A blood BB or BO AA or AO Gametes all B / 50% B and all A / 50% A and 50% O Frank can be BO = B blood …no worries

Grandparents AB and AB Mom=B blood possible BB or BO genotypes Gametes all B / 50% B and 50% O Frank can be BO or BB = B blood Dad=A blood AA all A …Uh-Oh

Pedigree, tracing the genetic past Dom. Rec. Dom.

We can also predict the future Fig 2. 12

Inheritance of blood types Mom = AB Dad = AB

Inheritance of blood types Mom = AB Gametes: A or B Dad = AB A or B

Inheritance of blood types Mom = AB Gametes: A or B Dad A or B A AA Mom or B AB Dad = AB AB BB Chance of each phenotype for each offspring 25% AA 50% AB 25% BB