Incomplete dominance and codominance Dec 13 & 14 Please get: Journal Handouts Karyotype grid and Chromosomes

Gametes, with only _____ of each chromosome pair are _________. Warm up for Dec. 13 & 14 Body cells, produced by the process of ______, are ______. This means that they have 2 of each chromosome. Gametes, with only _____ of each chromosome pair are _________. Gametes are produced by the process of _________.

Gametes, with only half of each chromosome pair are haploid. Warm up review Body cells, produced by the process of mitosis, are diploid. This means that they have 2 of each chromosome. Gametes, with only half of each chromosome pair are haploid. Gametes are produced by the process of meiosis.

PATTERNS OF INHERITANCE KEY CONTENT: PATTERNS OF INHERITANCE LEARNING TARGET: I CAN WORK OUT PROBLEMS THAT SHOW VARIOUS PATTERNS OF INHERITANCE

MENDEL WAS LUCKY….. or just really smart?!

Mendel Was Lucky...or just really smart?! The pea traits that Gregor Mendel selected exhibited simple dominance. We now understand that inheritance is rarely so simple!! What follow are some other ways that traits can be passed on.

NOTES: Incomplete Dominance The dominant allele is only weakly dominant over the recessive allele. Example: RR = red flowers rr = white flowers but Rr = pink flowers!

NOTES: Co-dominance The alleles for a gene are equally dominant and both are expressed in the phenotype. Example: B = brown fur W = white fur BW = fur composed of BOTH brown and white hairs.

Incomplete vs. Co-dominance

Co-dominance Another example of co-dominance is the gene that controls human blood type. Allele A is co-dominant with allele B. Both A and B are equally dominant over a 3rd allele, o. There are 4 human blood types….what are the phenotypes and genotypes for each??

Co-dominance PHENOTYPE GENOTYPE (S) TYPE A AA OR AO TYPE B BB OR BO TYPE AB AB TYPE O OO

Abo blood type

NOTES: Sex-linked Traits Some genes are located on the sex chromosomes (usually the X) and therefore have special inheritance patterns. Examples of X-linked recessive genes are: Red-green colorblindness Hemophilia Fruit fly eye color

Sex chromosome maps

Sex chromosome maps

Sex-linked Traits Colorblind Example: XX = female; XY = male XNXN = non-colorblind female XNXn = carrier* female XNY = non-colorblind male XnXn = colorblind female XnY = colorblind male NOTES: *Carrier: This is a person who carries the recessive gene but it is not expressed. This person has the ability to pass on the recessive gene to their offspring.

Complete your karyotype grid Check your chromosome smear with the normal karyotype to determine which chromosomal disorder is represented. Complete the Chromosomal Disorder Report…you may need to use a laptop to go online to find more information. Be prepared to report to the class. Complete your genetic problems packet Complete the genetic problems packet. Due next class.