the 23^rd pair that have either two homologous X chromosomes (XX=Female) or a non-homologous pair of X and Y, (XY=Male)

an orderes display of chromosomes and allows one to identify the 22 pairs and the sex chromosomes.  Used to identify conditions caused by chromosomal aberrations.

Polyploidy- when a cell has more than the diploid number (69 or 92)

Aneuploidy- a somatic cell that doesn’t contain a multiple of 23 Chromosomes (has one or two missing or an extra chrom.)

Triploidy- When a zygote with somatic cells has 3 copies of each chromosome rather than 2.

Tetraploidy-when cells have 92 chromosomes

Polyploidy majority all children conceived are either spontaneously aborted or die shortly after birth.

DS results from the presence of an extra copy of chromosome 21.

The term "trisomy" is used to describe the presence of an extra chromosome — or three instead of the usual pair;

The term "monosomy" is used to describe the absence of one member of a pair of chromosomes. Therefore, there are 45 chromosomes in each cell of the body instead of the usual 46

47- shows that there’s an extra chromosome; XY shows that it’s male; 21 means it’s in the 21^st pair of chromosomes.

-Most common is trisomy with 47 chromosomes.

With trisomy mosaicism, they will have some cells with the typical number of chromosomes (46) and some cells with can extra chromosome 21.  It can make for a less severe case of Down Syndrome.

1-in an abnormal fertilized egg with 47 chromosomes, one of the cells make lose the extra chromosome at cell division, leaving 26 chromosomes in that cell.  All cells from that cell with have 46 chromosomes.  The rest will have 47.

2- In a typical zygote with 46 chromosomes, at cell division, one of the cells may retain a duplicated copy of one of the chromosomes.  His produces a cell with 47 chromosomes.  All cells from that cell will have 47 chromosomes.  The rest will have 46.

Which of the following female associated chromosome aneuploidy would have the most severe mental and physical disabilities: XXX, XXXX, XXXXX

XXXXX- more severe mental retardation and various physical defects.

The ovaries do not develop because one of the X chromosomes is missing or misshapen in most of the cells, causing them to not go through puberty as a teenager and withholds the levels of estrogen needed to develop the ovaries, breasts, and menstruation.  Their stature is usually a great deal smaller than others.  The unterus and vagina are normal and there is no mental retardation due to Turner’s Syndrome.

What is the usually treatment for Turner syndrome when a girl nears 10 years? Reaches 13 or 14? Throughout her life?

At 10, she is given low does of biosynthetic growth hormone alond with estrogen to increase the growth rate.  At 13 or 14, she is given female hormones to bring about sexual development, and most women will have to take female hormone pills throughout their lives.

When considering XYY, what is effect does this male aneuploidy have on IQ? Inclination to commit violent crimes? Behavioral disorders?

Their abilities for intellectual function and educational attainment are lower.  That with the physical abonomalities such as height and acne and hyperactive, impulsive, and often times violent temper outbursts often lead to criminal behavior and violent crimes.

What is the genotype of Klinefelter’s syndrome?

Has extra sex chromosomes.

This syndrome causes the man to have larger breasts, smaller testes, poor facial hair growth, and inability to produce sperm.

What treatment of this condition will improve the physical and secondary sex characteristics? Developmental disabilities?

Regualar injections of testosterone beginning at puberty and surgery to change some of the visible aspects of the syndrome.

The main developmental issue is a language impairment.

can be used to detect visible congenital anomalies like spina bifida and malformations of the head, face, body, and limbs.  It can’t determine the biochemical or chromosomal alterations.

used to check chromosomes, can check for downs syndrome, spina bifida.

What are the two advantages of chronic villus sampling over amniocentesis? Risks?

Faster results, abortion much safer at this stage, but more dangerous for miscarriage and for digital or limb deficiencies.

Through unequal or uneven crossing over.  Produce gametes that are carrying deleted or duplicated genetic material.

Compare crossing over to translocation.

Crossing over- during meiosis, the homologous chromosomes normally pair up and exchange genetic alleles.

Traslocation- two non-homologous (different sets) chromosomes break and exchange fragments.

What is reciprocal translocation and how can it produce deletions and additions of genetic material in gametes?

Reciprocal translation- (even distribution) When there is no loss of genetic material.  This can still happen with gametes with a combination of duplication and deletion of genetic material. Meiotic division determines what is carried on.

Clastogens- increase point mutation.

UV light- cause a bump in the genetic material and can prevent the material from reaching the messenger rNA that will be translated to a protein.

Ex: ionized resonated, radiation, extreme heat, chemicals, tobacco, etc.

What would be more lethal, a child born with additional chromosome material or minus the normal amount of chromosome material?

Minus is more lethal.

Explain cri-du-chat syndrome (i.e., cause and symptoms).

“Cry of the cat”- deletion on 5^th chrom.  Critical for the neuronal circuit development.  Function on central nervous system.  The severity depends on the amount that is deleted.  Symptoms- motor capacity, muscle weakness, all systems are slowed in development.  IQ is low, intelligence is greatly effected.

P is dominant allele and produces the enzyme phenylalanine hydroxylase and that converts to phenylalanine tyrosine.  It has to do this because the phenylalanine will build up in the child’s system and it will affect their brain growth and maturity.

Small p is recessive and it does not produce the phenylalanine hydroxylase.  The gene is mute and doesn’t produce that enzyme.

If the child is homozygous dominant, it produces the enzyme, but if it’s homozygous recessive, then they may have it.  But giving strict guidelines for protein foods, it can control the amount of phenylalanine in their system. 

Explain dominance, recessiveness, and co-dominance in terms of the ABO blood type.

3 alleles:

AI producesàred cell membrane protein A

IB producesà red cell membrane protein B

IO producesà does not produce red cell A Membrane.

6 different types of genotypes:

Blood type A: either homozygous or homo A

B: homo B or heter B

AB: both proteins

O: homo O

A couple both have an autosomal dominant disease (both heterozygous), what is the risk of their first child having the disease? Their second child being born without the disease?

Gender does not matter:

Risk is 50% chance of having a child with it and without it.  Every childbirth is going to have a 50% chance. Each si independent.

Gender does not matter:

50% chance that they will and won’t.

Explain how the following conditions allow autosomal dominant diseases to stay within the gene pool of a population and give an example of each: delayed age of onset

Delayed onset: don’t know until ages of 30 and 40 and have lready passed it on to children.  That’s how it stays in the population.

Penetrance: if a disease has 95% pen. Then 95% can be born with the gene and have the diease, but 5% can have the dominant gene without showing the disease but can still pass it along.

Expressivity: variation of severity. Like (The elephant man) von reclehousen disease.  A child can be born with one or all.  Mild or severe.  It can still be passed along even if they don’t know and their child can have all.

90% who have the dominant gene will show signs of the disease and 10% can have the dominant gene but will show no signs of the disease but they can still pass it along.

100% chance that the child will be healthy.  There is a 0 percent chance that a child will be born with the disease. 50% chance that any children will be a carrier.

For an autosomal recessive disease, both husband and wife are carriers. If the first child is a girl, what is her risk of having the disease? Of being a carrier? Of being homozygous normal?

Gender doesn’t matter.

Any child born has a 25% chance that the child has the disease.  50% carrier but healthy w/out the disease.  25% chance of homozygouse normal.

For a X-linked recessive disease, the husband is normal and the wife is a carrier. What is the risk of a male child with the disease? A female child with the disease? A male child without the disease? A female child with the disease?

X linked disease the man can only be hemizygous because he only has one X and only carry one gene.  Male child: 50%

Female child: 0%

Male w/out: 50%

For a X-linked recessive disease, the husband has the disease (he is red-green color blind) and the wife is a carrier. What is the risk of a male child with the disease? A female child with the disease? A male child without the disease? A female child without the disease?

Male: 50%

Female child: 50%

Female w/out: 50%

Male w/out: 50%

Only the male is hemizygous bc he only has one X

Bc its X linked, it’s not really dominant.  It’s x linked in that if a male child was born with the x chromosome that is less than 200 repeats of CGG on the X chrom it won’t have the disease.  For the male it’s dominant and recessive. If it’s greater they have it.

Premutation: 50-200 repeats.  Full: greater than 200 repeats.

Fragile x: when the repeats is beyond 200 mehtylization with occur in that area so that the enzyme with read the gene and can’t get through.  It’s not a problem with the gene, it’s the enzyme RNA getting to the area and it knocks it off.  Causes mental retardation.

Fragile-X syndrome, the husband has 10 copies of the repeat on his X chromosome and the wife has one X chromosome with 35 copies of the repeat and the other X chromosome with 400 copies of the repeat. What is the chance for this couple to have a male child with the condition? A female child with the condition?

Male: 50% will be born with genotype

Female: 50% chance to be born with genotype.  Depends on mosaicism. 

     X35      X400

       X10  10/35  10/400

       Y       35Y     400 Y

If most chroms carrying 35 or 10, there’s a good chance that she will be more normal.

Mendelian: either dominant or recessive but no co-dominant.  Didn’t get the X link

Define multifactorial inheritance.

Polygenic, more than one allele.  One allele is not necessarily dominant

Environmental: has a large effect on certain conditions.

D-1 and D-2: decrease the risk by 2 and 1 increments

D+1, D+2: bad genes: increase the risk in 1 to 2 increments

39. What is the main environmental factor that influences the development of DM2?

Obesity (BMI greater than 30)

-Eating high calorie diets

-Don’t excersize

What are two factors that together are considered a single entity known as liability for DM2? As exemplified in this text, explain how one can reach the threshold for these two factors?

Genetic and environmental:

BMI greater than 30

Genetics: Incriments greater than 2

They’re a generation with bad genes.  8% prevalence in one area, but in another area it’s 50-70% prevalence.  They have bad genes but their lifestyles make it worse.