Genetics 1.4

separase

-This is the enzyme that breaks down cohesion so that the chromatids can separate.

dichotomous

An aid that is used to identify organisms and that consists of the answers to a series of questions

proband

In genetics research, the individual displaying the trait or characteristic being studied

consanguinity

Mating between closely related people

Concordance is high in

Monozygotic twins

1. Both males and females are usually affected; often more females than males are affected 2. Does not skip generations. Affected sons must have an affected mother; affected daughter must have either an affected mother or an affected father 3. Affected fathers will pass the trait on to all their daughters 4. Affected mother wills (if heterozygous) will pass the trait on to half of their sons and half of their daughters.

X-linked dominant trait

1. Usually more males than females are affected 2. affected sons are usually born to unaffected mothers, thus the trait skips generation 3. Approximately half of a carrier (heterozygous) mother's son are affected 4. Never passed from father to son 5. All daughters of affected father are carriers

X-linked recessive trait

1. only males are affected 2. Passed from father to all sons 3. Does not skip generations

Y-linked trait

chorionic villus sampling

a prenatal test to detect birth defects at an early stage of pregnancy (b/t 10th -12th week)

autosomal dominant traits

affected individuals always have an affected parent, disease appears in every generation, affected parents pass trait to both daughters and sons (not sex linked)

heterochromatization

all but one X chromosome in humans are inactivated by this. 1. Determination-perm. shut off

When a person with a rare trait mates with someone who has the normal gene from outside the family

all the children will be carriers of the gene but will not have the trait.

familial hypercholesterolemia

an autosomal dominant trait

X-linked dominant traits

appear in males and females, although they often appear more frequently in females. Does not skip generations, affected males pass the trait to all their daughters, but never their son.

APC/C

causes destruction of cohesion to start anaphase

Females in a pedigree is represented by

circle

klerokonesis

division of cytoplasm without mitosis; occurs in cells where normal cytokinesis fails and the cell has doubled the normal chromosome number. It's frequency of occurrence is not known but it occurs during G1.

noninvasive prenatal genetic diagnosis

do not require penetration of any embryonic structure

autosomal recessive traits normally appear with

equal frequency in both sexes and seem to skip generations

studies on adopted people help distinguish the difference between

genetic influence and environmental,

Genetic counseling

guidance for prospective parents on the likelihood of genetic disorders in their future children

Examples of X-linked dominant trait in human

hypophosphatemia, familial vitamin D resistant rickets

Monozygous twins

identical twin twins from same ovum, always same sex/blood group

Autosomal dominant traits appear

in both sexes with equal frequency. An affected person has an affected parent (unless the person carries a new mutation), and the trait does not skip generations. Unaffected persons do not transmit the trait

preimplantation genetic diagnosis

is a technique used to identify genetic defects in embryos created through in vitro fertilization (IVF) before transferring them into the uterus

because homozygotes are more severely affected than heterozygotes

it is said to be incomplete dominance (familial hypercholesterolemia)

heterozygote screening

members of a population are tested to identify heterozygous carries of recessive disease-causing alleles

Recessive traits appear _____frequently among the offspring of consanguine matings.

more

if an autosomal dominant allele is rare

most people displaying the trait are heterozygous

When a recessive trait is rare,

people from outside the family are usually homozygous for the normal gene

fetal cell sorting

separate fetal cells from maternal cells with the use of lasers and automated cell-sorting machines.

Males in a pedigree is represented by

square

The higher concordance in a monozygotic twins

suggest that genes influence a certain disease

X-linked recessive traits

tend to skip generations. Mostly males get the disease, but females can do if they receive two copies of the affected gene, pattern is: unaffected mother to affected son, ect. example: Hemophilia A

presymptomatic genetic testing

testing healthy adults for genes that might predispose them to a genetic condition in the future

newborn screening

tests performed to help early detection of disease, especially genetic disorders, at birth

If the rate of a certain disease is similar between monozygotic and dizygotic it means that

that disease does not have an inherited tendency

Concordance

the percentage of twin pairs that is concordant for a trait

in X-link dominant traits, affected females (if heterozygotes)pass

traits to 1/2 of the sons and 1/2 of their daughter.

Y-linked traits

very rare; transmitted male to male; no affected females

concordant

when both members of a twin pair have a trait

dynein

Also known as 'motor protein.' It powers flagellum. Also maybe involed in chromosomal movement.

securin

An APC target, inhibits sister chromatid separation

dizygotic twins

(Fraternal Twins)- Develop from separate eggs and separate sperm, making them genetically no more similar than ordinary siblings.

amniocentesis

(pregnancy) extraction by centesis of amniotic fluid from a pregnant woman (after the 15th week of pregnancy) to aid in the diagnosis of fetal abnormalities

pedigree

A diagram that shows the occurrence of a genetic trait in several generations of a family

karyotype

A display of the chromosome pairs of a cell arranged by size and shape. A picture of a complete set of metaphase chromosome

What differentiates an X-linked dominant inheritances from autosomal dominant inheritance?

A male can inherit a trait from his father in autosomal dominance inheritance but not in the X-linked dominant inheritance, because fathers only pass the Y gene to their son.

ultrasonography

A technique that uses high-frequency sound waves to create an image (scan) of body organs (also may be referred to as sonography or echography)

genetic information nondiscrimination act

Act that prohibits discrimination against individuals on the basis of their genetic information in both employment and health care.

habitus

All aspects of life are interconnected through social webs

1. Usually appear in both sexes with equal frequency 2. Both sexes transmit the traits to their offspring 3. Does not skip generations 4. Affected offspring must have an affected parent unless a new mutation occurred. 5. When one parent is affected (heterozygous) and the other is unaffected, approximately half of the offspring will be affected 6. Unaffected parents do not transmit the trait

Autosomal dominant trait

1. Usually appears in both sexes with equal frequency 2. Tends to skip generation 3. Affected offspring are usually born to unaffected parents 4. When both parents are heterozygous, approximately 1/4 of the offspring will be affected 5. Appears more frequently among the children of consanguine marriages

Autosomal recessive traits

direct-to-consumer-genetic tests

Genetic testing offered to anyone interested in investigating his or her own hereditary conditions without requiring a health care provider

discordant

If only one member of a twin has a trait

ubiquitin

Small protein that is linked to other proteins as a way of marking the targeted protein for degradation by proteasomes.

Maternal blood screening

Tests performed on a woman's blood to determine whether the fetus she is carrying has an increased risk for some types of chromosomal and metabolic disorders.

ploidy

The number of complete chromosome sets present. Haploid refers to a ploidy of 1; diploid refers to a ploidy of 2; triploid, a ploidy of 3; and tetraploid, a ploidy of 4