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Mathena

genetics

the branch of biology that studies the ways in which hereditary info is transmitted.

Hereditary Info

responsible for traits (inherited characteristics) of an individual

probability

the mathematical science that predicts the chance that a certain event may occur

hereditary

transmission of genes from one generation to the next

Mendel

known as the "father of genetics". He first tested DNA of pea plants and made rules about genetics

monohybrid cross

a cross between 2 individuals who are different for the same trait offspring called monohybrids

dihybrid cross

a cross between 2 individuals who are different for the same trait. offspring are called dihybrids

law of dominance

in a hybrid, the dominant trait is expressed over the recessive when paired together

law of ind. assortment

pair of genes separate independently of one another to form gametes. All possible genes may occur TtYy- TY Ty Yt ty

law of segregation (meiosis)

two alleles of a gene are segregated during gamete formation. so a gamete only carries one of each gene

karyotype

when geneticists collect and grow baby cells, match the chromosome pairs and look for genetic abnormalities

Sutton and bovers

discovered and wrote chromosome theory after reading and understanding Mendel's work

test cross

when an ind. has the dominant trait and wants to find what genotype it is, they cross themselves with the recessive genotype and look at their offspring to see what their genotype is

amniocentesis

a way to test the fetus for abnormalities by inserting a needle through the uteran wall into the amniotic sack where the baby's cells are

nondisjuction

cell division during which 2 sister chromatids fail to separate, causing abnormal gametes

down's syndrome

trisomy 21. occurs when nondisjunction causes the egg to carry both chromosomes and is then fertilized by another chromosome on the 21st pair. Causes child to have mental retardation, short stature do to retarded physical development, short stubby legs, hand, abnormally large face and possible congenital heart formations

turner's syndrome

when the individual has 45 chromosomes instead of 46 because it doesnt have a Y This happens when an egg does not contain an X chromosome and is fertilized by an X bearing sperm. These people are usually sterile and sexually underdeveloped, short, below average IQ and abnormalities in skin and skeleton

Kleinfelters syndrome

XXY. the egg was double the number of chromosomes and was fertilized by a Y bearing chromosome. causes extra tall people, usually die early. sexually underdeveloped.

Thomas Morgan

He won a nobel prize for his work with genetics. he studied fruit flies and discovered X-linked traits

drosophilia

fruit flies

x-linked traits

traits only carried by the female X chromosome ex. red green colorblindness and hemophilia

carriers

women who have one of their chromosomes marked with the disease

Sickle-cell anemia

is when the blood cells are shaped like a sickle, causing them to not carry as much oxygen to the body. example of codominance because heterozygous people for sickle-cell anemia have both full and sickle cells

Phenylketonuria (PKU)

a person does not have the ability to break down phenylalinine and that lessens the production of melanin

Tay-Sachs

recessive disorder in autosomes where the person cannot break down fatty acids and they accumulate in the brain, causing mental problems.

polyploidy

when you have more than one set of chromosomes. common in plants because it makes them strong. lethal in humans, rare in animals.

gene linkage

genes that travel together during gamete formation

gene mapping

marking the order in which the genes are placed on a chromosome

sex determination

being XX or XY depending on which sperm fertilizes your egg

monosomy

when there is only one chromosome in a pair

trisomy

when there is three chromosomes in a pair

hemophilia

an x-linked disease where the blood cannot clot itself

color-blindness

an x-linked disease where one cannot see colors clearly

deletion

when a nucleotide is deleted from the sequence, example of frameshift mutations

addition

when a nucleotide is added to the sequence

inversion

when a segment of a chromosome detaches itself and flips itself around, messing up the sequence.

translocation

when a segment of a chromosome detaches itself and moves to another homologous pair

polygenic (multiple gene) inheritance

when more than one family gene affects the final outcome

cystic fibrosis

when there are no chloride ions and the chloride makes the water in one's body get thick and mucus-like, clogging up respiratory system and digestive system!!!!

chorionic villus sampling

genetic testing where a sample is taken from the baby's chorion (like a pre-placenta) which contains the baby's cells

ultrasound

the use of high frequency sound waves to monitor the baby's growth and appearance while in the womb

fetoscopy

when a small camera is placed in the woman's VAGINA!!! and is used to see the baby directly in the womb and can also have a sample taken from it or something

sex influenced traits

having certain traits more common for males and females

sex limited traits

controlled by autosomal genes that can be only found in the sex. ex. making of female and male reproductive organs

jumping genes

when a gene on a chromosome moves from one point to another on the same chromosome

mutagens

they cause mutations

point mutations

are when a nucleotide is replaced with another nucelotide

frameshift mutations

additions and deletions in the sequence. If this mutation is a deletion, it causes everything to move over

Huntington's disease

it affects the nervous system. symptoms include slow loss of brain function, uncontrollable movements and emotional disturbances

Super Female

XXX. When an egg having two chromosomes is fertilized by an X-bearing sperm. These XXX females have a tendency towards learning disabilities, most have no apparent physical abnormalities

Edward's Syndrome

Trisomy 18. results from an extra chromosome in the 18th pair autosomes. they usually die, have a small chin, a long head, and their fingers are permanently flexed

fetal blood sampling

when blood is drawn directly from the baby in the womb and is used to test for genetic problems

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