chromosomal abnormalities I

Question 1

chromosomal abnormalities that arise during meiosis

Answer 1

germ line mutations

Question 2

reciprocal recombination events between maternal and paternal sister chromatids occur when?

Answer 2

during prophase I

Question 3

physical linkages between homologous chromosomes are called? how many of these per chromosome?

Answer 3

chiasmata (crucial for normal chrom disjunction); 2-3

Question 4

does recombination occur during mitosis?

Answer 4

very rare

Question 5

total genetic variability

Answer 5

80^23

Question 6

things that happen during prophase I (in order)

Answer 6

• chromosomes begin to condense and align
• synaptonemal complex forms
• synapsis is complete (chroms appear as a bivalent (tetrad))
• recombination
• at this point, homologues are only held together by chiasmata

Question 7

metaphase I

Answer 7

spindle forms, certromeres align on equitorial plane

Question 8

anaphase I

Answer 8

• members of each bivalent move apart

- attached sister chromatids are drawn to opposite poles of the cell during disjunction

Question 9

telophase I

Answer 9

the two haploid sets of chromosomes are grouped at opposite poles and citokinesis happens

Question 10

the process of pairing chromosomal DNA

Answer 10

synapsis (during prophase I)

Question 11

ribbon like, protein containing structure essential for recombination

Answer 11

synaptonemal complex (early prophase I)