Meiosis and Transmission Genetics

chromosome

a thread-like structure made of tightly wound DNA and proteins that carries genetic information from cell to cell

telomere

a protective cap made of repetitive DNA found at the ends of our chromosomes

acrocentric chromosome

a chromosome where the central joining point sits very close to one end

metacentric chromosome

chromosome that has its central connecting point (called the centromere) right in the middle

centromere

the narrow, pinched middle part of a chromosome

telocentric

chromosome where the centromere is located right at the very end

karyotype

a picture of a person's chromosomes used to spot genetic disorders, missing or extra chromosomes, or broken chromosome pieces

meiosis

a reduction division over 2 rounds of division that results in the formation of four haploid gametes

interphase

cell grows, copies its DNA, and gets ready to divide

prophase I

Chromosomes condense, and synapsis (the close pairing of two homologous chromosomes) happens and homologs separate a little bit

metaphase I

pairs of homologous chromosomes line up side-by-side along the middle of the cell

anaphase I

paired homologous chromosomes are pulled apart to opposite ends of the cell

telophase I and cytokinesis

wrap up the first round of meiosis by splitting one cell into two new haploid cells

prophase II

chromosomes condense and spindle fibers form in two new cells

metaphase II

the stage of cell division where individual chromosomes line up along the middle of a haploid cell before being pulled apart

anaphase II

sister chromosomes split apart and move to opposite sides of the cell

telophase II and cytokinesis

divide cells into four unique, final reproductive cells

number of rounds of division

mitosis - 1

meiosis - 2

number of progeny cells

mitosis - 2

meiosis - 4

are the daughter cells identical?

mitosis - yes

meiosis - no

ploidy change

mitosis - N → N; 2N → 2N

meiosis - 2N → N

separation of homologous chromosomes

mitosis - no

meiosis - yes; anaphase I

separation of sister chromosomes

mitosis - yes; anaphase

meiosis - yes; anaphase II

monosomy

loss of a chromosome

trisomy

addition of a chromosome

allopolyploids

organisms that have 2 or more full sets of chromosomes from two or more different species

Robertsonian Interchange

two different chromosomes fuse together into one large chromosome