From genes to organisms

How do genes work?
Meiosis
DNA Code

Review

Other kinds of inheritance
Non-Mendelian

Incomplete Dominance (flower color)

	Y gamete	y gamete
Y gamete	YY	Yy
y gamete	Yy	yy

Other Kinds

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Genetics of Blood-types

Multiple co-dominant alleles
- 3 alleles, A, B, or O on chromosome 9
  A and B are co-dominant
  O is recessive.
- Type AB blood has AB alleles.
- Type 0 blood has only the O allele.
- Other ABO Combinations
Other Blood Types.

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Dominant alleles are not necessarily more common than recesive ones

Blood Type	U.S.A. Ave%	Japanese	Native American
A	40%	39%	16%
B	10%	22%	4%
AB	4%	10%	1%
O	46%	29%	79%

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Sex Chromosomes

SRY

If SRY is present, testes develop in the embryo
If SRY is absent, ovaries develop

Most mammals: ♂ XY, ♀ XX
Most birds: ♂ ZZ ♀ ZW "heterogamety"
Some reptiles gender is determined by the incubation temperature of their eggs. (link) + pic
Abnormalities

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MEIOSIS: making gametes +

	PROPHASE I homologous chromosomes pair
	METAPHASE I align at equator
	ANAPHASE I homologous chromosomes separate
	TELOPHASE I haploid chromosome number
	PROPHASE II begin 2^nd division
	METAPHASE II chromosomes at equator
	ANAPHASE II chromatids separate
	TELOPHASE II four hapolid gametes

Review Meiosis Mitosis

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MEIOSIS

(in gonads) Transfroms diploid cell into 4 haploid gametes.
Produces mix of father and mother's genetic material
Meiosis produces mutations that increase genetic variability (anaphase I)
- crossovers, inversions
- extra & missing chromosomes
movie 1 2 3

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From Genes to Organisms

DNA > RNA > Protein > Enzymes

Translation Transcription

Primary structure of proteins
is the sequence of Amino Acids

(Peptide Bonds)

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CODON: a sequence of 3 nucleotides in mRNA that selects for an Amino Acid.
" A genetic 'code word' containing three 'letters.' "
" More than one 'word' for each amino acid. "