chromosone and human genetics (exam 2)

why genetic matter?

Why siblings look different despite having the same parents, Why some diseases run in families, DNA ancestry testing, Personalized medicine, Genetic disorders such as Down syndrome or sickle cell disease

DNA

genetic molecule that Carry information, made of (A, T, C,G)

gene

segment of DNA contain instruction for specific trait each gene provide instruction for protien

chromosone

long DNA molecule tightly coiled and packaged with protiens each chromosone contain many genes

cell(nucleus)

chromosone are found in the nucleus

human traits

gene working together to influence our observable traits

chromosome composition

number and type have similarities across the

same species – varying considerably in size and shape

metacentric

near the middle

submetacentric

off center

acrocentric

near one end

telocentric

at one end

chromosonal abnormality

Changes to the number,structure, or length of chromosomes, and existing genetic material within

banding pattern

size and centromere location

chromosone stained create?

G-bands

G-band signifigance

identification and distiguished

changes in total amount of genetic material

deletion and duplication

heritable changes

break and rejoin chromosone

chromosonal rearrangment

inversion,transloaction

2 type of translocation

simple,reciproical translocation

deletion

segment of chromosome is removed becoming deficient in genetic material

duplicaction

segment of chromosome occurs 2 or more times

inversion

change in the direction of genetic material along a chromosome,

leading to changes in the order of G-bands

reciprocal transloaction

2 different chromosomes exchange pieces by an abnormal crossing-over event, producing 2 abnormal chromosomes

simple translocation

single piece of a chromosome becomes attached to a single chromosome

variation occurance

In the number of chromosomes sets and the number of

specific chromosomes

euploid

chromosomes that occur in one or more sets

polyploid

3 or more sets of chromosomes

triploid

3n

tetraploid

4n

anueploidy

An alternation in the number of a particular chromosome, so the

chromosomes will not be an exact multiple set (trisomy = 2n + 1)

nondisjunction

an event where chromosomes don’t properly separate

during cell division, can occur during Meiosis I or II, producing haploid cells with too many or too few chromosomes

abnormality

lead to production of organisms resulting in abnormalities or disorders.

can abnormality be benificial

yes

eukaryotic occurance

in sets, composed of different types of chromosomes.

sex chromosome

xx,xy

autosome

autosomal chromosome

homologous chromosomes are alike or disalike?

exaclty alike in length,size and amount of genetic information

how are autosomal chromosone labled

largets to smallest

x-large, carrie how many protien coding gene ?

900

y-small,carrie how many protien coding gene ?

50

sex-linked gene

Y-linked exist in minimum

x-linked gene

more genes are found on X that are not present on Y

haplodiploid system

does not require a pair of sex chromosomes, some can form sex in the presence or absence of a sex chromosome

enviromental sex determination

Some instances chromosomes are not involved; in some reptiles and fish the environment can contribute to one vs the other

sex determination in plants

most species are a diploid plant (sporophytes) that makes both male and female gametophytes. However, some sporophytes can have 2 sexually distinct individuals

homologous chromosone

SAME genes, but may contain different versions of those genes

incomplete dominace

genes not showing reccessive/dominant

incomplete dominace in heterozygote

separate alleles exist, and the organism shows an intermediate phenotype between the phenotypes of 2 homozygous individuals

codominance

Effects of 2 genes are equally visible in the phenotype of a heterozygote organism

variation

Genes create the phenotype; environment provides nutrients to execute

norm of reaction

the range of the phenotype an organism can exhibit in

variable environments

Autosomal recessive genetic disorders

individuals with such must have heterozygous parents, making them genetic carriers

Autosomal dominant genetic disorders (rare)

which are commonly a result of a spontaneous mutation

locas(loci)

A region of a single gene on a chromosome

Amniocentesis

A small sample of amniotic fluid is withdrawn and analyzed.

Chorionic villus sampling (CVS)

A small tissue sample from the placenta

Non-invasive prenatal testing (NIPT)

A maternal blood test that analyzes cell-free DNA from the fetus

Preimplantation Genetic Testing (PGT)

Used in IVF to screen embryos for genetic abnormalities before transferring them to the uterus.

pedigree analysis

analyzes inherited traits over generations, can be less definitive

because of small groups