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Male parents generally DO NOT Contribute cytoplasm to zygotes SO… mitochondria and chloroplasts are MATERNAL CONTRIBUTIONS Cytokinesis (Cell Division) -actin microfilaments and Karyokinesis (Nuclear division, including mitosis) -tubulin microtubules Model for organelle division From Dec 2003 Science …..without implications for segregation Maternal effect (NOT Maternal inheritance) Genetic/genomic imprinting Maternal imprinting Paternal imprinting If neither copy of 15q11 has paternal imprinting, the result is Prader-Willi syndrome (characterised by hypotonia, obesity, and hypogonadism). If neither copy has maternal imprinting, the result is Angelman syndrome (characterised by epilepsy, tremors, and a perpetually smiling facial expression). גנטיקה של אוכלוסיות Formula for allele frequency, based on knowledge of genotypes A 3 allele case In 3 allele case, same mathematical treatment p = freq of IB = freq B (IBIB) + ½ freq of B (IBi) + ½ freq of AB (IBIA) q = freq of IA = … r = freq of i = … p+q+r=1 YET: Populations with different genotypes can have the same allele frequency BUT, if there are random matings, the genotype frequency of offspring is based on solely on the allele freq. In next generation Hardy-Weinberg (H-W) Law (& Chetverikov) YET, if there are random matings, the genotype frequency of offspring is based on solely on the allele freq. Populations NOT in H-W equilibrium In next generation Hardy-Weinberg (H-W) Law In this case: If the processes below do not occur, a population is in Hardy-Weinberg (HW) equilibrium, the following are unchanged: Allele frequencies Genotype frequencies Phenotype frequencies TEST: if these populations are in H-W equilibrium, then: If a population is in Hardy-Weinberg equilibrium, the allele,genotype, and phenotype frequencies will be stable as long as the HW requirements hold H-W בשיווי משקל-- הרבה אכלוסיות תיאור של אכלוסיה לפי תדירויות...אז )' מתאים (ו'חסכוני- של אללים 2 allele case Genotype frequencies Genotype frequencies M/M N/N M/N p(M) q(N) We see HW equilibrium for ‘breeding populations’ We don’t expect HW for, say: the city of New York City Lots of immigration Not random matings, but many distinct sub-groups BUT, MANY human populations are in H-W equilibrium, for exampleMN tables we just saw, and: Percent Location MM MN NN p q Iceland 31.2 51.5 17.30 0.57 0.43 Greenland 83.5 15.6 0.9 0.92 0.08 How do HW populations “start” with different allele frequecies? In human populations, often small founder populations: How do HW populations “start” with different allele frequecies? In human populations, often small founder populations: Percent Location MM MN NN p q Iceland 31.2 51.5 17.30 0.57 0.43 Greenland 83.5 15.6 0.9 0.92 0.08 If the processes below do not occur, a population is in Hardy-Weinberg (HW) equilibrium, the following are unchanged: Allele frequencies Genotype frequencies Phenotype frequencies If these processes DO occur, the populations change. -Each process can be studied and quantitated Selection of allele A: preferential survival Haplotype Inbreeding 0.5 X 0.5 ללמוד בבית על Migration Source of variation, deviation from HW: migration (M) into a population P is the allelic frequency in the donor population And p0 is the original frequency among the recipients M-migration rate Originally Yamane – not resistance to Gefilte-fish Poland – 0.42 are resistance to Gefilte-fish Current- among Yamane 0.046 are resistance Thus DPtotal 0.046-0 P-P0 is 0.42-0 M= 0.046/0.42=1.095 Inbreeding Source of variation: deviation from HW: mutations have a slow effect on allele frequency (here, of w.t.): Jan 3 start Pseudo male - female cross in neurospora Allele names according to phenotype amorph NULL R~ R~ hypomorph Wild type R R hypermorph R R neomorph R~ R~ Standard Dominant – Recessive Haploinsufficiency