Chromosomes

Nondisjunction

________ is caused by: error in homolog separation in anaphase I and sister chromatid separation in anaphase II.

Trisomy

________: three chromosomes in a gamete.

Polyploidy

________: entire extra set of chromosomes; common in plants.

Genetic map

________: an ordered list of loci along a chromosome.

Barr body

________: the inactive, condensed X chromosome.

Fruit

________ flies produce 100s of offspring, new generation every 2 weeks, only 3 autosomal and 1 sex chromosome.

Trisomy X

________: shows no difference from the normal XX.

Nondisjunction

________: gametes having one extra and one less chromosome.

wild type

the normal/most common phenotype in natural populations

mutant

the opposite of wild type

sex-linked/X-linked

genes located on sex/X chromosome

Genetic map

an ordered list of loci along a chromosome

genetic map was constructed by

Sturtevant, Morgans student

linkage map

created by associating frequencies of recombinants along the chromosomes

For a female to express a recessive sex-linked allele, she must be

homozygous recessive

hemizygous

only one locus(one X to be expressed)

X-linked recessive disorders

re-green color blindness, Duchenne muscular dystrophy, hemophilia

X-inactivation

only one of two X chromosomes are active in each cell

Barr body

the inactive, condensed X chromosome

Calico cats are only female, only male when

XXY (Klinefelters)

Nondisjunction

gametes having one extra and one less chromosome

Nondisjunction is caused by

error in homolog separation in anaphase I and sister chromatid separation in anaphase II

aneuploidy

abnormal chromosome number

trisomy

three chromosomes in a gamete

monosomy

one chromosome

polyploidy

entire extra set of chromosomes; common in plants

trisomy 21

down syndrome

Klinefelters

extra X chromosome

Jacobs syndrome

extra Y chromosome

trisomy X

shows no difference from the normal XX

Turners Syndrome

monosomy X

Cri du chat

deletion in chromosome 5

Leukemia

reciprocal translocation