Bonus #2 due 11/25 Meiosis and Genetic Diversity

Is this the best I can do? Maybe I can find someone with better genes or more genetic diversity. Am I the only one? Am I better off helping with these kids or should I mate with someone else?

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

Gene for blue eye pigment Gene for brown hair pigment Gene for growth hormone Haploid chromosomes Gene for hemoglobin Gene for DNA polymerase

Gene for hemoglobin Gene for hair color Gene for growth hormone Allele for black hair Allele for black hair Allele for low express (short) Allele for high express (tall) Allele for normal Hb Allele for sickle cell Hb Diploid chromosomes

Each pair of chromosomes is comprised of a paternal and maternal chromosome Fig 1.5

meiosis DiploidHaploid Fig 1.11

Fig 3.16 Meiosis splits apart the pairs of chromosomes. X 23 in humans

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

Fig 3.12 sister chromatids= replicated DNA (chromosomes) tetrad= pair of sister chromatids

Fig 3.16 Meiosis splits apart the pairs of chromosomes. X 23 in humans

extremely low genetic diversity greater genetic diversity vs. Asexual Reproduction Sexual Reproduction How does sexual reproduction generate genetic diversity?

Fig 3.10 DNA cut and religated Crossing-over (aka Recombination)

Crossing-over: Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes. Fig 3.10

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

Crossing-over: Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes. Fig 3.10

extremely low genetic diversity greater genetic diversity vs. Asexual Reproduction Sexual Reproduction How does sexual reproduction generate genetic diversity?

Fig 3.17 Independent Assortment (aka Random Assortment)

Independent Assortment 2 possibilities for each pair, for 2 pairs 2 2 = 4 combinations Fig 3.17

Independent Assortment 2 possibilities for each pair, for 23 pairs 2 23 = 8,388,608 combinations Fig 3.17

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

Fig 3.12

4 haploid cells Fig 3.12

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

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

Do parents’ genes/traits blend together in offspring?

In many instances there is a unique pattern of inheritance. Traits disappear and reappear in new ratios. Fig 2.6

from DNA to Protein: from gene to trait Fig 1.6

Cellular Organism Population Molecular from DNA to Protein: from gene to trait Fig 1.7

GenotypePhenotype

Human blood types Fig 4.11

One gene with three alleles controls carbohydrates that are found on Red Blood Cell membranes RBC A A A A A A A A A B B B B B B B B B Allele A = A carbsAllele B = B carbs Allele O = no carbs Fig 4.11

Human blood types Fig 4.11

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

RBC A A A A A A A A A Recessive alleles do not show their phenotype when a dominant allele is present. Genotype could be A and A OR A and O See Fig 4.2

What about… Genotype = ?? RBC

What about… Genotype = OO RBC

A A A B A A B B B What about… B

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

Human blood types AA or AO AB BB or BO OO Fig 4.11

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

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

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

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

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

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

Fig 2.11

We can also predict the future Fig 2.6

Mom = ABDad = AB Inheritance of blood types

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

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

Single genes controlling a single trait are unusual. Inheritance of most genes/traits is much more complex… Dom.Rec. Dom.

PhenotypeGenotype Genes code for proteins (or RNA). These gene products give rise to traits…

Human blood types AA or AO AB BB or BO OO Fig 4.11

PhenotypeGenotype Genes code for proteins (or RNA). These gene products give rise to traits… It is rarely this simple.

Incomplete dominance Fig 4.3

Fig 4.4

Bonus #2 due 11/25