 Dear teacher this was adapted from a presentation by:  Nancy Dow  Jill Hansen  Tammy Stundon  Who teach in Bay County  The missing words have been noted for each slide in the “Click to add notes” space at the bottom of each slide.

B ENCHMARK SC.912.L.16.1* Use Mendel's laws of segregation and independent assortment to analyze patterns of inheritance. (HIGH) SC.912.L.16.2* Discuss observed inheritance patterns caused by various modes of inheritance, including dominant & recessive which are simple inheritance & codominant, sex-linked, polygenic, and multiple alleles (complex inheritance). (HIGH)

For Humans: 23 homologous pairs; one chromosome form mom and the other from dad Karyotype - display of pairs of chromosomes Autosomes are chromosomes 1-22 Chromosome pair 23 is your sex chromosomes

 Gene - a section of DNA that codes for a ________  Allele – Any form of a specific gene. You get ____ from each parent.  Dominant Allele - ______case letter  Recessive Allele - ______case letter

 Karyotype - the display of the pair of chromosomes with highlighted alleles  Phenotype - the physical _________ of the alleles  Genotype - allele __________ for a gene of an individual Bb, BB, or bb (B is the dominant allele, b is the recessive allele)  Trait - term for distinguishing phenotypic features or ______________

INHERITANCE OF GENES Maternal chromosome pair Paternal chromosome pair Gene Paternal gamete: spermMaternal gamete: egg Gametes unite during fertilization. Child inherits one set of chromosomes from each parent and, thus, two copies of each gene. Humans have 23 pairs of chromosomes (46 individual chromosomes) and, thus, two copies of each gene. Each human gamete has just one copy of each chromosome and, thus, one copy of each gene. ALLELES

What traits will be expressed? For simple inheritance, you only need _____Dominant allele for the Dominant trait to be expressed. Naturally, the only way for a Recessive trait to be expressed is if the person has ______ Recessive alleles. Exceptions   

 Heterozygous - a __________ and a _________ allele (Bb) (also called hybrid)  Homozygous dominant - ____ dominant alleles (BB) (also called Purebred)  Homozygous recessive - ____ recessive alleles (bb) (also called Purebred)  Only one dominant allele need to be present to be expressed

 The Punnett square is a grid system for predicting all __________ genotypes resulting from a cross.  The axes represent the possible _________ of each parent.  The boxes show the possible _________ of the offspring. The Punnett square yields the ratio of possible ___________and ____________.

 __________ crosses examine the inheritance of only ____specific trait.  homozygous dominant X homozygous recessive  Genotype: all heterozygous (100%)  Phenotype: all dominant (100%)

PUNNETT SQUARE: ALBINISM A Punnett square is a useful tool for determining the possible outcomes of a cross between two individuals. GAMETES A A Aa a a OFFSPRING GenotypePhenotype All heterozygous Aa All pigmented FATHER pigmented homozygous AA MOTHER albino homozygous aa Cross 1 (F 1)

–If you cross a heterozygous with a heterozygous (Ff X Ff) –What is the genotypic ratio of the offspring? –1:2:1 homozygous dominant: heterozygous: homozygous recessive; (25%:50%:25%) –What is the phenotypic ratio of the offspring? –3:1 dominant: recessive (75%:25%)

GAMETES A a AAAa aa A a OFFSPRING GenotypePhenotype FATHER pigmented heterozygous Aa MOTHER pigmented heterozygous Aa Cross 2 (F2) 1/4 homozygous dominant AA 2/4 heterozygous Aa 1/4 homozygous recessive aa 3/4 pigmented 1/4 albino 3:1 RATIO Your genotype and phenotype results are presented separately

If you cross a heterozygous with homozygous recessive (Ff X ff) What is the genotypic ratio? 1:1 heterozygous: homozygous recessive What is the phenotypic ratio? 1:1 dominant: recessive

A ___________is a cross between an organism with an unknown genotype and an organism with the recessive phenotype Why use the recessive phenotype to test an unknown?

 ____________is the likelihood that something will happen.  Probability predicts an average number of occurrences, not an exact number of occurrences. Probability = number of ways a specific event can occur number of total possible outcomes Probability applies to _________ events such as meiosis and fertilization.

GENETICS AND PROBABILITY IF… The mother is albino, and the father is heterozygous THEN… There is a 100% chance that the mother’s egg will carry the recessive a allele and a 50% chance that a sperm will carry the recessive a allele aaAa 100% 50% aaAa AND… 0.5 or 50% chance the offspring will be albino. Multiply the two components together to determine the overall probability. = aa ×

Goat genetics

 Mendel’s dihybrid crosses with heterozygous plants yielded a 9:3:3:1 phenotypic ratio. Mendel’s dihybrid crosses led to his second law, the ______________________ _______________. The law of independent assortment states that allele pairs separate independently of each other during meiosis.

Dihybrid Cross: a cross that shows the possible offspring for two traits Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth In this example, we will cross a heterozygous individual with another heterozygous individual. Their genotypes will be: BbRr x BbRr

Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth BbRr x BbRr BR bR br bR Br BR br Br Then, find the possible genotypes of the offspring

Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth BbRr x BbRr BR bR br bR Br BR br Br BBRRBbRRBbRr BBRrBBrrBbRrBbrr BbRRBbRrbbRRbbRr BbRrBbrrbbRrbbrr BBRr

BR bR br bR Br BR br Br BBRRBbRRBbRr BBRrBBrrBbRrBbrr BbRRBbRrbbRRbbRr BbRrBbrrbbRrbbrr BBRr How many of the offspring would have a black, rough coat? How many of the offspring would have a black, smooth coat? How many of the offspring would have a white, rough coat? How many of the offspring would have a white, smooth coat? Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth

 Nancy Dow  Jill Hansen  Tammy Stundon