Natiwya Saddler Mitchell Loll 4.3.2 - 4.3.11

Background Info Genotype: the alleles of an organism Phenotype: all characteristics of an organism Punnett Square: means of finding the expected ratio of the offspring, given certain parental phenotypes Monohybrid: cross of parents that are homozygous except for a single gene locus that has two alleles (RR and rr)

Cont. Allele: member of a pair or series of genes that occupy a specific position on a specific chromosome Homozygous: having the same alleles at a particular gene locus on homologous chromosomes Heterozygous: having different alleles at on or more corresponding chromosomal loci. Locus: position a gene occupies on a chromosome

4.3.2 Determine the genotypes and phenotypes of the offspring of a monohybrid cross using a Punnett Grid http://www.siskiyous.edu/class/bio1/genetics/monohybrid_v2.html

What is a Punnett Square? Created in early 1900’s by Reginald Punnett depicts the number and variety of genetic combinations All possible offspring of two parents for each gene

4.3.3 State that some genes have more than two alleles (multiple alleles). Multiple Alleles: When more than two alleles control a trait these are known as multiple alleles.

4.3.4 Describe ABO blood groups as an example of co-dominance and multiple alleles

Co-Dominance: Situation in which two different alleles for a genetic trait are both expressed Red plant + White plant =

4.3.5 Explain how the sex chromosomes control gender by referring to the inheritance of X and Y chromosomes in humans Both males and females have X Only males have Y Receive Y from your dad ½ chance of being male

4.3.6 State that some genes are present on the X chromosome and absent from the shorter Y chromosome in humans X chromosome is much larger X-linked genes only appear on X chromosome Colorblindness Hemophilia More common in males

4.3.7 Define Sex Linkage Sex Linkage: the phenotypic expression of an allele that is dependent on the gender of the individual directly tied to the sex chromosomes. Occurs when genes carried on sex chromosomes Most often on X chromosome

4.3.8 Describe the inheritance of color blindness and hemophilia as examples of sex linkage Both most common in males Produced by recessive sex-linked allele on X chromosome ½ of males receive colorblindness

4.3.9 State that a human female can be homozygous or heterozygous with respect to sex linked genes Females have two X chromosomes Homozygous: both alleles are the same Dominant or Recessive Heterozygous: different alleles. One dominant, one recessive

Males have only one X chromosome Homozygous and heterozygous do not apply

4.3.10 Explain that female carriers are heterozygous for X-linked recessive alleles Woman can carry traits without being effected Men have one chromosome, one allele will be expressed

This mother was a carrier for hemophilia but was not effected by the condition. Half of her sons will carry have hemophilia Y chromosome carries no allele

4.3.11 Predict the genotypic and phenotypic ratios of offspring of monohybrid crosses involving any of the above patterns of inheritance ¼ = GG Homozygous Dominant ½ = Gg Heterozygous ¼ = gg Homozygous Recessive

Practice Punnett Square One Height in plants T=tall T=short T t

½ Homozygous Dominant ½ Heterozygous T TT t Tt

Genotype: ½ Homozygous Dominant ½ Heterozygous Phenotype: 100% Tall Plant

Punnett Square Two Eye Color in Humans B= Brown b= Blue B b

Punnett Square Two Eye Color in Humans B b BB Bb bb

Genotype: ¼ Homozygous Dominant ¼ Homozygous Recessive ½ Heterozygous Phenotype: ¾ Brown eyes ¼ Blue eyes

Punnett Square Three Hair C= Curly Hair B= Bald b C

b C Cb bb

Genotype: ½ Heterozygous ½ Homozygous Recessive Phenotype: ½ Curly Hair ½ Bald

Punnett Square Four Dwarfism D= dwarf N= normal proportion D n

D n Dn nn

Genotype: ½ Heterozygous ½ Homozygous Recessive Phenotype: ½ Dwarf ½ Normal Proportion

Punnett Square Five Blood Type A B o

Punnett Square Five Blood Type A B AA AB o

Genotype: ½ A blood ¼ AB blood ¼ B blood Phenotype: ½ A blood ¼ AB blood ¼ B blood