A&P II Ch. 29

allele

version of a gene

for every gene there are two

amniocentesis

fetal genetic testing method (14-16th week)

stick a needle into abdomen and amniotic sac and take a sample of amniotic fluid

• takes a while

autosomes

chromosomes 1-22

the non sex chromosomes

homologous pairs

chorionic villus sampling

fetal genetic testing (8-10 weeks)

insert suction tube up the vagina and cervix, and suction off some of the chorionic villi which have fetal cells

• can test right away

• more invasive and risky

codominance

all alleles are expressed equally - not a blend

• blue eyes + brown eyes = one brown and one blue eye

complete dominance

heterozygous genotype

dominant allele completely masks the recessive allele

• red + yellow = red

diploid

cell containing two complete sets of chromosomes

has all 46 chromosomes (or 23 homologous chromosomes)

dominant

the allele/version that is expressed if it is present

homo or heterozygous dominant (HH, Hh)

genotype

for any one gene, explanation o the type of allele

• (dominant, recessive, homozygous, heterozygous)

haploid

a cell that contains a single set of unpaired chromosomes (egg and sperm)

heredity

the study of how traits are passed from parent to offspring

heterozygous

different version/allele on each chromosome for a particular gene

homologous chromosomes

two copies of all of the genes; same genes on each chromosomes within each pair

homozygous

same version/allele on each chromosomes for a particular gene

incomplete dominance

heterozygous genotype

the phenotype will be a blend of both

• red + yellow = orange

intersex

someone who has a disconnect between sexual characteristics and the typical sexual characteristics

• binary

• chromosomal reason/hormonal effect

karyotype

picture of the chromosomes sorted by size

Klinefelter’s syndrome

XXY chromosomes

micropenis/male genitalia but female body type

meiosis

produces four unique haploid sex cells for reproduction

reduces the number of chromosomes in gametes

nondisjunction

when there is an unequal separation of the chromosomes

pedigree

chart where you map the genotype of a particular gene through several generations

phenotype

physical expression of the gene (based on genotype)

• H = brown eyes

recessive

this is the allele/version that is only expressed in the absence of a dominant allele - homozygous recessive (hh)

sex chromosomes

the 23rd pair of chromosomes (XX or XY)

have a lot of genes encoded on them that determine sexual characteristics

synapsis/crossing over

during prophase, the replicated chromosomes bind together

exchange of homologous chromosomes/DNA

• mother = oocytes/gametes whose chromosomes are a blend of her mother and father

• father = haploid sperm whose chromosomes are a blend of his mother and father

Turner syndrome

only have one sex chromosome (XO)

effects development in the womb

XX

long

biological female

homologous pair

XY

short

biological male

not homologous pair