GENETICS +EVOLUTION

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Genes

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-Fundamental units of hereditary material
-Locus: location of gene on chromosome
-Chromosome: 22 autosome, 2 sex chromosome, 23 pairs of chromosomes (only one sex chromosome in each)
-Allele: different version of genes. 2 alleles, one version on each homologous chromosome
-Homozygous: same version of alleles on each chromosome (HH, hh)
-Heterozygous: different version of alleles (Hh)
-Dominant: Allele expressed when heterozygously paired
-Recessive: Allele not expressed when homozygously paired
-Phenotype: physical expression of genes

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Terms in this set (35)

Genes

Meiosis

-4 copies of haploid gametes (not identical- recombination occurs
-occurs in testes/ ovaries
-spermatogonia + oogonia undergo meiosis
-S phase: replicates genome.
Replication ->mitosis -> meiosis I -> meiosis II
-Prophase I: chromosomes condense, nuclear envelope breaks down.
-Synapsis: homologous chromosome pair with each other into a tetrad
-crossing over or recombination occurs
-Metaphase I: alignment along metaphase plate. Tetrads align not sister chromatids
-Anaphase I: Homologous chromosomes separate randomly. at this point, cells are considered haploid
-Telophase I: separation
-Prophase II-Metaphase II: same thing, no recombination
Anaphase II: sister chromatids separate
-Telophase II: 4 separated haploid cells

Nondisjunction

when homologous chromosomes (meiosis I) or sister chromatids (meiosis II) fail to separate

Mendalion Genetics:

Law of Segregation

2 alleles of individuals are separated then passed on to next generation singly