Chromosome

a discrete package of DNA and associated protein

Autosomes

non-sex chromosome, chromosomes that are the same for both sexes.

Sex chromosomes

determines whether an individual is male or female

Which sex chromosomes do females have?

Two X chromosomes; XX

Which sex chromosomes do males have?

an X and Y chromosome; XY

When a cell is not dividing, how do its chromosomes look?

its chromosomes are very loosely packed in the nucleus and are therefore not visible

Karyotype

a size-ordered chart of all the chromosomes in any cell of an organism.

Which characteristics that uniquely identify each chromosome are illustrated by Karotypes?

size, banding pattern, and centromere position

Size (in reference to chromosomes)

Autosomes are numbered based on size. 1 is the largest 22 is the smallest

Banding patterns

stains applied to chromosomes highlight unique 

patterns of light 

a dark-staining band, which differ among the chromosome types

Centromere

a centromere is a characteristically located constriction in a chromosome

Linked genes

are carried on the same chromosome; they are therefore inherited together.

Gene linkage

changes the results of a Dihybrid cross.

Crossing over

an exchange of genetic material between homologous chromosomes during meiosis.

Recombinant chromosomes

have a mix of maternal and paternal alleles

Parental chromosomes

retain the allele combinations from each parent

Linkage maps

are diagrams of gene order and spacing on chromosomes

Breaking linkage

crossing over is more likely to separate the alleles of genes A and B (or A and C) than to separate the alleles of genes B and C because there is more room for an exchange to occur

Autosomal dominant

inheritance pattern of a dominant allele on an autosome

True or False: When someone has an autosomal dominant allele, the phenotype effects the males and females equally and can skip a generation. 

False; when someone has an autosomal recessive allele this is true.

Autosomal recessive

 inheritance pattern of a recessive allele on an autosome

When someone has an autosomal dominant allele, the phenotype affects the male and female equally and does not skip generations.

True

Pedigree

are charts that simultaneously depict family inheritance patterns for a phenotype.

Sex-linked

describes genes or traits on the X or Y chromosome

X-linked

describes genes and traits on the X chromosome

X-activation

a cell shuts off all but one X chromosome in each cell, a process that happens early in the embryonic development of a mammal

True or False: X-linked recessive disorders are more common in males that in females

True; because males have only one X chromosome to a female’s two