Human Inheritance

Other forms of Inheritance Genetics is not simple.Genetics is not simple. There are more complex gene interactions that occur other than what we term “simple Mendelian genetics”There are more complex gene interactions that occur other than what we term “simple Mendelian genetics”

Multiple Alleles Some Human traits are controlled by a single gene that has more than two allelesSome Human traits are controlled by a single gene that has more than two alleles Such genes are said to have Multiple AllelesSuch genes are said to have Multiple Alleles

Incomplete Dominance Incomplete dominance when neither allele is dominant over the other and a blending of the traits is the result.Incomplete dominance when neither allele is dominant over the other and a blending of the traits is the result. Snapdragons (Flowers) are an example.Snapdragons (Flowers) are an example.

Co-Dominance Co-dominance is when both alleles are dominant and both traits show in the genotype.Co-dominance is when both alleles are dominant and both traits show in the genotype. Blood Groups are an example.Blood Groups are an example.

Blood types Human blood type is controlled by a gene with multiple alleles.Human blood type is controlled by a gene with multiple alleles. There are 4 main blood types:There are 4 main blood types: Blood Type ABlood Type A Blood Type BBlood Type B Blood Type OBlood Type O Blood Type ABBlood Type AB

Blood Types The alleles for Blood type A and B are dominant.The alleles for Blood type A and B are dominant. The allele for blood type O is recessiveThe allele for blood type O is recessive

Blood Types GenotypePhenotype AA or AO Blood Type A BB or BO Blood Type B AB Blood Type AB OO Blood Type O

Can you complete the following Punnett Squares? A O BBGenotypePhenotype

BA O O GenotypePhenotype

What Image do you see? Ishihara Test : What numbers do you see revealed in the patterns of dots below? Image A Those with normal colour vision should read the number 8. Those with red-green colour vision deficiencies should read the number 3. Total colour blindness should not be able to read any numeral. Image B Normal colour vision should read the number 5. Those with colour vision deficiencies will not read the number or read it incorrectly.

What Image do you see? Image C Normal colour vision should read the number 15. Red-Green deficiencies should read the number 17. Total colour blindness should not be able to read any numeral. Image D Both normal and those with all colour vision deficiencies should read the number 12.

What Image do you see? Image E Image F

Sex Linked Traits

Sex Chromosomes The sex chromosomes are one of 23 pairs of chromosomes in each body cell.The sex chromosomes are one of 23 pairs of chromosomes in each body cell. The sex chromosomes carry genes that determine weather a person is a male or female.The sex chromosomes carry genes that determine weather a person is a male or female.

In other words Mother ( Female) is XXMother ( Female) is XX Father ( Male) is XYFather ( Male) is XY The Y chromosome is much smaller than the X chromosome.The Y chromosome is much smaller than the X chromosome.

Complete the Punnett Square Complete the Punnett square in your note sheetComplete the Punnett square in your note sheet What are the chances of having a baby boy?What are the chances of having a baby boy? What are the chances of having a baby girl?What are the chances of having a baby girl?

Is it a Boy or Girl? XX XX XY XY XX XX XY XY X X X Y 50% chance of having a girl 50% chance of having a boy Brainpop Gender Determination

Sex Linked Genes Genes that are located on the x chromosome are called sex linked genes.Genes that are located on the x chromosome are called sex linked genes. It is called an x-linked trait and is only carried on the x chromosome.It is called an x-linked trait and is only carried on the x chromosome.

Sex Linked Genes Red-green colorblindness, hemophilia, and male pattern baldness are examples of sex-linked (x) traits.Red-green colorblindness, hemophilia, and male pattern baldness are examples of sex-linked (x) traits.

Who is a carrier? A carrier is a person who has one recessive allele for a trait and one dominant allele.A carrier is a person who has one recessive allele for a trait and one dominant allele. Although the carrier does not have this trait, the carrier can pass the recessive allele on to his or her offspring Although the carrier does not have this trait, the carrier can pass the recessive allele on to his or her offspring Carriers are usually Females (Think XX)Carriers are usually Females (Think XX)

Colorblindness Key GenotypePhenotype X c Color Blind Female XcXXcXFemale carrier XYNormal Male XcYXcYColorblind Male

Will there offspring be color blind? Cross a normal female with a color blind maleCross a normal female with a color blind male GenotypePhenotype

Will there offspring be color blind? Cross a carrier female with a normal maleCross a carrier female with a normal male GenotypePhenotype

Will there offspring be color blind? Cross colorblind female with a colorblind maleCross colorblind female with a colorblind male GenotypePhenotype BrainPop Genetics

Pedigrees Pedigrees are charts that are used to study the inheritance of a trait within a family, or on a larger scale, within a closely related populationPedigrees are charts that are used to study the inheritance of a trait within a family, or on a larger scale, within a closely related population

Pedigrees Pedigrees are useful in showing the information known about individuals within a family, and with the collection of enough information, can help deduce the genotypes of each family member.Pedigrees are useful in showing the information known about individuals within a family, and with the collection of enough information, can help deduce the genotypes of each family member.