One of the key differences between experts and novices is an experts ability to recognize important information from less important information. Today: Inheritance for 1 gene

Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes. {Producing more cells} {Producing gametes} Fig 12.3

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 13.4

GenotypePhenotype

Human blood types Box 44.2

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 Box 44.2

Human blood types Box 44.2

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

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 Box 44.2 Phenotyp e Genotype Phenotype Result of transfusion

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

Some simple dominant/recessive relationships in humans Dom.Rec. Dom.

We can also predict the future Fig 2.12

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

Testcross: determining dominant/ recessive and zygosity

Fig Sickle-cell anemia is caused by a point mutation

Sickled and normal red blood cells

Mom = HSDad = HS H or S HH HSSS HS possible offspring 75% Normal 25% Sickle-cell Mom Dad S=sickle-cell H=normal Sickle-Cell Anemia: A dominant or recessive allele?

Coincidence of malaria and sickle-cell anemia

Mom = HSDad = HS H or S HH HSSS HS possible offspring Oxygen transport: 75% Normal 25% Sickle-cell Malaria resistance: 75% resistant 25% susceptible Mom Dad Sickle-Cell Anemia: A dominant or recessive allele? S=sickle-cell H=normal

Variation in pea shape and color

Phenotype Genotype Fig 13.5

The inheritance of genes on different chromo- somes is independent.

Y y rR Gene for seed color Gene for seed shape Approximate position of seed color and shape genes in peas Chrom. 1/7Chrom. 7/7 Fig 13.8

The inheritance of genes on different chromosomes is independent: independent assortment

Fig 13.8 meiosis I meiosis II

Fig 13.8 The inheritance of genes on different chromosomes is independent: independent assortment

Fig 13.5