Genetics:Genetics:

Inheriting TraitsInheriting Traits

ChromosomesChromosomes

• Chromosomes are columns of coiled DNA.

• You have 2 sets from chromosome 1-23 (46 total)

• Chromosomes are columns of coiled DNA.

• You have 2 sets from chromosome 1-23 (46 total)

Genes and TraitsGenes and Traits

• Genes are rows on the column of chromosomes that code for a trait. (instruction manuals)

• Traits are a notable feature or quality in a person. (physical, behavioral, medical conditions)

• Genes are rows on the column of chromosomes that code for a trait. (instruction manuals)

• Traits are a notable feature or quality in a person. (physical, behavioral, medical conditions)

Mr.. Emery?

QuestionQuestion

1) How many different chromosomes do you have?

2) How many sets of these chromosomes do you have?

3) What are chromosomes made of?

1) How many different chromosomes do you have?

2) How many sets of these chromosomes do you have?

3) What are chromosomes made of?

AnswersAnswers

1) How many different chromosomes do you have?1) 23

2) How many sets of these chromosomes do you have?1) 2

3) What are chromosomes made of?1) Tightly wound columns of DNA

1) How many different chromosomes do you have?1) 23

2) How many sets of these chromosomes do you have?1) 2

3) What are chromosomes made of?1) Tightly wound columns of DNA

Genotypes vs. Phenotypes

Genotypes vs. Phenotypes

• Genotype: The type of genes that make up a trait. They are expressed in letters and come in pairs (WW, Ww, ww)

• Phenotype: An observable trait (widows peak) or the expression of the genotype.

• [from Greek phaino- shining, from phainein to show]

•The individual letters are called alleles. (W) or (w)

• Genotype: The type of genes that make up a trait. They are expressed in letters and come in pairs (WW, Ww, ww)

• Phenotype: An observable trait (widows peak) or the expression of the genotype.

• [from Greek phaino- shining, from phainein to show]

•The individual letters are called alleles. (W) or (w)

Dominant vs. Recessive Traits

Dominant vs. Recessive Traits

• Dominant traits: When two different traits are paired (widows peak vs.. straight hairline) the dominant trait shows.

• Dominant traits are usually expressed genetically with an upper-case letter of the dominant trait (W)

• Dominant traits: When two different traits are paired (widows peak vs.. straight hairline) the dominant trait shows.

• Dominant traits are usually expressed genetically with an upper-case letter of the dominant trait (W)

Dominant vs.. Recessive TraitsDominant vs..

Recessive Traits• Recessive traits: are ‘hidden’ when paired up with a dominant trait.

• Recessive traits are most often expressed genetically with a lower-case letter of the dominant trait.• Straight hairline is expressed with (w), not an (s). The (w) matches the (W) for the dominant trait, a widows peak.

• Recessive traits: are ‘hidden’ when paired up with a dominant trait.

• Recessive traits are most often expressed genetically with a lower-case letter of the dominant trait.• Straight hairline is expressed with (w), not an (s). The (w) matches the (W) for the dominant trait, a widows peak.

QuestionQuestion

Widows peak is dominant trait over a straight hairline .

1) If the genotype is (Ww), what phenotype will be expressed?

2) If the genotype is (ww), what phenotype will be expressed?

3) Why is (ss) not a good set of letters for this trait?

Widows peak is dominant trait over a straight hairline .

1) If the genotype is (Ww), what phenotype will be expressed?

2) If the genotype is (ww), what phenotype will be expressed?

3) Why is (ss) not a good set of letters for this trait?

AnswersAnswersWidows peak is dominant trait over a

straight hairline .1) If the genotype is (Ww), what

phenotype will be expressed?1) Widows peak

2) If the genotype is (ww), what phenotype will be expressed?1) Straight hairline

3) Why is (ss) not a good set of letters for this trait?1) The letter representing the trait

should be of the dominant trait.

Widows peak is dominant trait over a straight hairline .

1) If the genotype is (Ww), what phenotype will be expressed?1) Widows peak

2) If the genotype is (ww), what phenotype will be expressed?1) Straight hairline

3) Why is (ss) not a good set of letters for this trait?1) The letter representing the trait

should be of the dominant trait.

Homozygous vs. Heterogygous

Homozygous vs. Heterogygous

• Homo: same• Hetero: different• Zygous: yoked, or joined

• Homo: same• Hetero: different• Zygous: yoked, or joined

Homozygous vs. Heterozygous

Homozygous vs. Heterozygous

• Homozygous: same genes or trait

• (WW) and (ww) are both homozygous.• (WW) is homozygous, and dominant• (ww) is homozygous, and recessive

• Heterozygous: different genes or trait• Ww is heterozygous, that’s it.

• Homozygous: same genes or trait

• (WW) and (ww) are both homozygous.• (WW) is homozygous, and dominant• (ww) is homozygous, and recessive

• Heterozygous: different genes or trait• Ww is heterozygous, that’s it.

QuestionQuestion

Widows peak is dominant over a straight hairline.1) What is the genotype of a

homozygous dominant trait for widows peak?

2) If the genotype is heterozygous for widows peak, which phenotype will be ‘hidden?’

3) What trait will be expressed if someone is homozygous, recessive?

Widows peak is dominant over a straight hairline.1) What is the genotype of a

homozygous dominant trait for widows peak?

2) If the genotype is heterozygous for widows peak, which phenotype will be ‘hidden?’

3) What trait will be expressed if someone is homozygous, recessive?

AnswersAnswers

Widows peak is dominant over a straight hairline.1) What is the genotype of a homozygous

dominant trait for widows peak?1) WW, not ww

2) If the genotype is heterozygous for widows peak, which phenotype will be ‘hidden?’1) Straight hairline

3) What trait will be expressed if the someone is homozygous, recessive?1) Straight hairline

Widows peak is dominant over a straight hairline.1) What is the genotype of a homozygous

dominant trait for widows peak?1) WW, not ww

2) If the genotype is heterozygous for widows peak, which phenotype will be ‘hidden?’1) Straight hairline

3) What trait will be expressed if the someone is homozygous, recessive?1) Straight hairline

Twins Identical twins vs. Fraternal twins

Twins Identical twins vs. Fraternal twins

• Identical twins: share the same genetic code.

• They come from the same egg and sperm.

• Identical twins: share the same genetic code.

• They come from the same egg and sperm.

Twins?Twins?

• Fraternal twins: Not identical genetically. They are like brothers and/or sisters born at the same time.• By the way, these two are NOT twins, however they are brother and sister. These pictures were taken approximately the same time developmentally and in the same clothes.

• Fraternal twins: Not identical genetically. They are like brothers and/or sisters born at the same time.• By the way, these two are NOT twins, however they are brother and sister. These pictures were taken approximately the same time developmentally and in the same clothes.

Cougar fans:Same age vs.. present

Cougar fans:Same age vs.. present

(A)

(B)

#1 #2

Can you match the Cougar Fans same age vs.. present?

QuestionQuestion

• These two Cougar fans are not fraternal twins.

1) Could their DNA be even more closely related than a pair of fraternal twins?

• These two Cougar fans are not fraternal twins.

1) Could their DNA be even more closely related than a pair of fraternal twins?

AnswerAnswer

• Yes, it is possible.

• And A=1, B=2

• Yes, it is possible.

• And A=1, B=2