BIOLOGY 2 - 46 chromosomes (carriers of genes, move and...

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46 chromosomes (carriers of genes, move and reside) 23 pairs of homologous chromosome of humans Homologous chromosomes have the same genes 1-22 (pairs) is autosomes 23 rd pair is sex chromosomes (xx female; xy male) Diploid – 2 sets of chromosomes, one chromosome from each parent Process of meiosis makes gametes Gametes are a set of chromosomes (23, haploid) Similar/related species have similar number of chromosomes Chromosomes are composed of 2 chromatins, which are connected at the centromere (maybe in the center or be in symmetric) Monosomic is 2n-1 Prophase I 4 chromosomes (2 long, 2 short) Homologous chromosomes Metaphase Are paired in the equator of cell (center) Anaphase I Separation of homologous chromosomes Chromosome disjunction Telaphase I 2 cells, each with one long and short chromosome Prophase II No pairing, each cell has 1 long, 1 short Metaphase II Each cell lined up at the equator, no pairing Anaphase II Chromatin disjunction Going to opposite poles Telaphase II End up with 4 cells Each with one chromatin of each type Result of meiosis: series of gametes, each with a set of chromosomes
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Look up Monohybrid Cross is a method of determining the inheritance pattern of a trait between two single organisms A dihybrid cross is a cross between F1 offspring (first generation offspring) of two individuals that differ in two traits of particular interest. For example: RRyy/rrYY or RRYY/rryy parents result in F1 offspring that are heterozygous for both R and Y (RrYy) Test cross is used to determine if an individual is exhibiting a dominant trait is homozygous or heterozygous for that trait. Put more simply testcrosses determine the genotype of an individual with a dominant phenotype. If a couple has a black baby, but the father is white and the mother is white, how would you draw the punnet square for the baby? In this example, white would be the dominant characteristic (W) and black the recessive (w) and both parents would have to be carrying the recessive allele. (The big W stands for the dominant and the w for the recessive alleles.) The punnet square would then look like the following: NB: Parent 1 and 2 both have the genotype Ww, because they carry both a dominant and a recessive allele. ___ W ____ w ___ W | WW | Ww w | Ww | ww Resulting in the phenotype (physical appearance) ratio : 3/4 - White, 1/4 – Black 3:1 And the genotype (combination of alleles) ratio : 1/4 - WW, 2/4 - Ww, 1/4 – ww 1:2:1 Test cross - cross between a dominant phenotype and a homozygous recessive, determine id its homozygous D or heterozygous. aabbcc – produce abc gamete, because each gamete gets one of each gene Traits controlled by many genes- polygenic Phenotype determined by number of “+”, the more “+” the darker you’ll be Quantitative- continuous trait (ex: height) Phenotype -> genotype and environment Phenotype variations- peppered moth, (natural selection) Genotypic variation Genotype + environment = phenotype Hardy-Weinberg P^2+2pq+q^2
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This note was uploaded on 01/30/2012 for the course BIO 311D taught by Professor Reichler during the Fall '08 term at University of Texas.

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BIOLOGY 2 - 46 chromosomes (carriers of genes, move and...

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