Genetics

Unit 3.2

Meiosis

is the process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

haploid and diploid

haploid= 1 set of chromosomes "gamete" (in a human n=23)

  • haploid is an egg without its mate

diploid= 2 sets of chromosome "normal" ( in humans 2n=46

  • diploid is anything sexually produced

homologous chromosomes

are chromosomes that have a corresponding chromosomes from the opposite sex parent ( for the same trait)


  • homologous means same trait

crossing over

is an exchange of portions of chromatids genetic material between 2 homologous chromosomes

mendelian genetics

genotypes and phenotypes

  • Genotypes are the sets of alleles
  • phenotype is the physical expression of the set of alleles
  • alleles- is one of a number of of alternative forms of the same gene or same genetic locus

Examples

Aa x Aa phenotype- 3 tall, 1 short hybrids= Aa/Aa


genotype- 1 AA 2 Aa 1aa per-bread= AA/aa

AA= tall 1 to 2 to 1 ratio

Aa= tall punnett square F1= offspring

aa= short




If there are dominates the big letter will be what happens

a tall allele will be dominate

probability

is the likelihood of an event occurring

  • gamete formation is random use probability to predict
  • use a punnett square to predict outcomes of a cross

F1 anf F2

If ever asked to do F2, F1 has to have homozygous alleles so all the outcomes are the same to began F2 phase