BIO.7 - GENETICS NON-MENDELIAN GENETICS

Incomplete Dominance In Heterozygous genotypes a COMBINATION of alleles are expressed (somewhere in the middle)

Incomplete Dominance Both alleles partially show by blending together Example: Mixing Paint yellow + blue = green

Incomplete Dominance ***Use two different letters to represent each allele, both letters are capital***

INCOMPLETE DOMINANCE Neither allele is dominant over the other. **Heterozygous genotypes demonstrate blended phenotypes

RWR RR W WW RR W W Homozygous Incomplete dominance R = Red and W = White RR x WW

RWR RR W WW RR W W 100% pink offspring Incomplete dominance

RRR RW W WW RW R W Heterozygous Incomplete dominance

RRR RW W WW RW R W Heterozygous Incomplete dominance

RW R W Heterozygous A 1:2:1 ratio with 25% red, 50% pink & 25% white offspring Heterozygous Incomplete dominance

Codominance In Heterozygous genotypes BOTH alleles are expressed (you see BOTH traits)

CODOMINANCE Both alleles are completely expressed at the same time. Example: Mixing Pebbles Yellow + Blue = Yellow AND Blue

Use two different letters, both are capital (same as incomplete dominance) CODOMINANCE

T = Tan and B = Black TT x BB T B T B TB

INCOMPLETE AND CODOMINANCE a) Birds can be blue, white, or white with blue-tipped feathers. b) Flowers can be white, pink, or red. c) A Who can have curly hair, spiked hair, or a mix of both curly and spiked. d) A Bleexo can be spotted, black, or white. e) A Sneech can be tall, medium, or short. Codominance Incomplete Dominance Codominance Incomplete Dominance

In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette. a. What is the genotype for black chickens? b. What is the genotype for white chickens? c. What is the genotype for erminette chickens? BB BW WW

If two erminette chickens were crossed, what is the probability that: They would have a black chick? ____% They would have a white chick? ____% BW W BBB WW BW

In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white (W). The heterozygous genotype is expressed as pink. a. What is the phenotype of a plant with the genotype RR? ___________ b. What is the phenotype of a plant with the genotype WW? ___________ c. What is the phenotype of a plant with the genotype RW? ___________ Red Pink White

A pink-flowered plant is crossed with a white- flowered plant. What is the probability of producing a pink-flowered plant? ____% RW W W RW WW RW WW

BIO.7 - GENETICS BLOOD TYPES

Multiple Alleles More than 2 alleles for 1 trait Blood type = 3 alleles A is codominant B is codominant o is recessive

PHENOTYPE GENOTYPE Type A Type B Type AB Type O AA (Homozygous Dominant) or Ao (Heterozygous) BB (Homozygous Dominant) or Bo (Heterozygous) AB (Codominant) oo (Homozygous Recessive)

Type AB = Universal Receiver Type O = Universal Donor

BLOOD TYPE PROBLEMS What are the two genotypes possible for a person who as A blood? What genotype does a person with AB blood have? What genotype does a person with O blood have? What are the two genotypes possible for a person who as B blood?

A man with type AB blood is married to a woman also with type AB blood. What blood types will their children have and in what proportion? BLOOD TYPE PROBLEMS A B A B AA BB AB

A man has type B blood (genotype BB) is married to a woman with type O blood. What blood type will all of their children have? What is the genotype of the children? BLOOD TYPE PROBLEMS B B o o Bo

A woman with type A blood (genotype Ao) is married to a type B person (genotype Bo). What proportion of their children with have: A blood? _______ B blood? _______ O blood? _______ BLOOD TYPE PROBLEMS A o B o AB oo Bo Ao

A woman with type A blood is claiming that a man with type AB blood is the father of her child who is also type AB. Could this man be the father of the child? Show the possible crosses; remember that the woman can have AA or AO genotypes. A A BAB o Bo Ao AA A A BAB A AA

A man with type AB blood is married to a woman with type O blood. They have two biological children and one adopted child. Marie has type A blood, Shawn has type B blood, and Ethan has type O blood. Which child was adopted? A B o o Ao Bo Ao

BIO.7 - GENETICS KARYOTYPES AND GENETIC DISORDERS

Karyotype The number of homologous chromosomes and what they look like Used to determine chromosomal disorders Nondisjunction – mutation caused by a failure of chromosomes to separate

Karyotype Autosome: pairs 1-22 in a human karyotype 23 rd pair determines sex

Is this karyotype male or female? FEMALE

Where is the abnormality in this karyotype? Down’s Syndrome

Where is the abnormality in this karyotype? Turner’s Syndrome

Is this karyotype male or female? MALE

Where is the abnormality in this karyotype? Klinefelter’s Syndrome

BIO.7 - GENETICS SEX-LINKED TRAITS

SEX-LINKED INHERITANCE A. We have 23 pairs of chromosomes B. Pair 23 determines sex XX = Female XY = Male Sperm cells can have X or Y

SEX-LINKED INHERITANCE Sex-Linked traits only carried on the X chromosome NO alleles on the Y chromosome

SEX-LINKED INHERITANCE Female Male Normal With Trait Carrier *Sex Linked Traits occur more in males than females (males cannot be carriers) XHXHXHXH XhXhXhXh XHXhXHXh XHYXHY XhYXhY

COLORBLINDNESS TEST On the next slide, silently read the numbers that are written in each picture. Make a note of the numbers that you can see. If you cannot see a number, do not write down anything.

EVERYONE SEES 12 EVEN COLOR BLIND PEOPLE NORMAL SEES 2 COLOR BLIND SEES NOTHING NORMAL SEES 8 COLOR BLIND SEES NOTHING NORMAL SEES 29 COLOR BLIND MAY SEE SOMETHING NORMAL SEES 45 COLOR BLIND SEES NOTHING NORMAL SEES 5 COLOR BLIND SEES NOTHING NORMAL SEES 6 COLOR BLIND SEES NOTHING EVERYONE SEES 56 EVEN COLOR BLIND PEOPLE NORMAL SEES 7 COLOR BLIND SEES NOTHING

SEX-LINKED IN HUMANS Colorblindness – difficulty distinguishing similar colors C = normalc = colorblind Cross Female Carrier with Normal Male X C YXC XcXC Xc

SEX-LINKED IN HUMANS All Normal Females 50% Normal Males

SEX-LINKED IN HUMANS Hemophilia – blood doesn’t clot properly Xh YXh Y XH XhXH Xh Normal Heterozygous Female Male with Hemophilia

SEX-LINKED IN HUMANS ½ Offspring has hemophilia

X G Y X g Y X g X G X g X G

XgYXgY X G X g XGXgXGXg XGYXGYXGYXGY

X g XGYXGY

yes no 2:2

BIO.7 - GENETICS PEDIGREE CHARTS

Pedigree A chart that shows how a trait is passed through several generations of a family

Pedigree Symbols Make a chart with 8 rows. Make 2 lines per row.

Pedigree Symbols Male Female

Pedigree Symbols Marriage Offspring

Pedigree Symbols or Person with the trait or Heterozygous (carrier)

Pedigree Symbols Roman Numerals (I, II, III) generations Numbers (1, 2, 3) individuals