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Genetics:. Inheriting Traits. Chromosomes. Chromosomes ____________________________________. You have ___sets, from chromosome ____-____ (______ total). Genes and Traits. Genes are _____________________________ of chromosomes that code for a _________. (instruction manuals)
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Genetics: Inheriting Traits
Chromosomes • Chromosomes ____________________________________. • You have ___sets, from chromosome ____-____ • (______ total)
Genes and Traits • Genes are _____________________________ of chromosomes that code for a _________. (instruction manuals) • Traits ______________________________________ ___________________ • Types of traits: 1)_______________ • 2)_______________ • 3)_______________ Mr. Emery?
Question • How many different chromosomes do you have? • How many sets of these chromosomes do you have? • What are chromosomes made of?
Genotypes vs. Phenotypes • Genotype: _________________________________________. They are expressed in letters and come in pairs (WW, Ww, ww). • Phenotype: _____________________________________________________________________ (widows peak) • [from Greek phaino- shining, from phainein to show] • The individual letters are called alleles. (W) or (w) (probably not on exam)
Dominant vs. Recessive Traits • Dominant traits: When two different traits are paired (widows peak vs. straight hairline) ___________________________________________. • Dominant traits are usually expressed genetically with an upper-case letter of ___________________________________ (W)
Dominant vs.. Recessive Traits • Recessive traits: are __________________ when paired up with a dominant trait. • Recessive traits are expressed genetically with a lower-case letter of the ________________________________________________________________________. • Straight hairline is expressed with (w), not an (s). The (w) matches the (W) for the dominant trait, a widows peak.
Question Widows peak is dominant trait over a straight hairline . • If the genotype is (Ww), what phenotype will be expressed? • If the genotype is (ww), what phenotype will be expressed? • Why is (ss) not a good set of letters for this trait?
Homozygous vs. Heterozygous • Homo: _______________ • Hetero: ______________ • Zygous: ______________
Homozygous vs. Heterozygous • Homozygous: ______________________ • (WW) and (ww) are both homozygous. • (WW) is homozygous, and _____________ • (ww) is homozygous, and ______________ • Heterozygous: __________________________ of genes or trait • Ww is ____________________________, that’s it.
Question Widows peak is dominant over a straight hairline. • What is the genotype of a homozygous dominant trait for widows peak? • If the genotype is heterozygous for widows peak, which phenotype will be ‘hidden?’ • What trait will be expressed if someone is homozygous, recessive?
TwinsIdentical twins vs. Fraternal twins • Identical twins: share ____________________________________. • They come from the same __________and ________________.
Twins? • Fraternal twins: Not identical genetically. They are like brothers and/or sisters ______________________________________. • By the way, these these two are NOT twins.
Cougar fans:Same age vs. same time (A) #1 #2 Can you match the Cougar Fans same age vs. same time? (B)
Question • These two Cougar fans are not fraternal twins. • Could their DNA be even more closely related than a pair of fraternal twins?