Homologous chromosomes may carry different alleles for any given gene.
In meiosis I, homologues pair and then segregate to different daughter cells
The alignment of one homologous pair is independent of the other homologous pair during
metaphase, therefore two possible combinations.
Recombination occurs during meiosis I, more specifically prophase I. REQUIRES GETTING
DNA FROM DIFFERENT CELLS INTO CLOSE PROXIMITY. Occurs when homologous
haploid parental genomes are brought into close proximity with each other. The recombination is
caused by the cutting, pasting, and exchanging of DNA molecules (repair of DNA in a way),
yielding cells with different DNA sequence that those carried by either parent. ALL
CHROMATIDS PAIR, NOT JUST THE INSIDE ONES! 3-D STRUCTURE, NOT 2-D!
The independent alignment of recombined chromosomes in meiosis II results in many different
The random fertilization of gametes (n) results in several possible zygotes (2n).
Virtually only in animals is the haploid a gamete. Most time spent in mitosis rather than meiosis,
diploid is multicellular.
In most plants and fungi, spores are the haploid, rather than gametes.
In some fungi and in algae, the haploid are multicellular, while the diploid are unicellular.
Binary fission is an asexual process, and is used by bacteria to reproduce.
The transfer of the F Factor involves an F+ donor, and a F- recipient, where the F plasmid is
reproduced by “rolling” while transferring into the F- recipient.
Bacterial genes can be transferred in a way similar to recombination, in that bridges are built
between two circular chromosomes, and they simply “roll” to form a combined chromosome.
This is known as integration. Conjugation or the movement from one cell into another cell of
chromosomes, the remnant chromosomes from the donor cell become degraded after conjugation
T4 Phage involves a virus attaching to a cell, whose restriction enzymes are unable to stop
infections, resulting in the host’s chromosomes being cut up. T4 phage chromosomes now in cell
and start multiplying, and begin being given out to other T4 phage “bodies”, thus allowing them
to multiply and continue spreading. The lytic cycle is how a virus develops and how the virus is
Transduction is the movement of DNA from one cell to another through the life cycle of a virus;
it can then be recombinated into the chromosome, which will help promote resistance to the virus.
Transformation is the natural ability of a cell to take up DNA from its environment.
The typical Mendelian ratios (3:1, 1:2:1, 9:3:3:1) are only seen if the traits show complete
dominance, have only two alleles, are coded by only one gene, are unaffected by the
environment, and are carried on autosomes (non-sex chromosomes).
Principle of Independent Assortment is the principle that the alleles of the genes that govern two