GENETICS 2 Complex Patterns of Inheritance How is

GENETICS 2 Complex Patterns of Inheritance

How is sex determined? In humans, the specific chromosomes that control the inheritance of sex characteristics X named. Ythe ____ and ___ chromosomes. are Both genders have two sex chromosomes: XXhave ____ and males XY have ____. Female * *Think of the “y” in boy

Are you colorblind? What number do you see?

Are you colorblind? What number do you see?

Are you colorblind? What number do you see?

Why are more males colorblind than females? Genes which are located on the sex chromosomes are said to be sexlinked _______. � Not all genes on the sex chromosomes control gender (i. e. color-blindness and hemophilia) • Colorblindness is a sexlinked trait. The gene that controls it is located on the X chromosomes

Why are some traits more common in men than women? Sex-linked traits occur more frequently in _____because they have only 1 ______ X chromosome. men If disorders are recessive, a female needs 2 copies of it to get the disorder while men only need 1. They don’t have a second allele to “mask” the recessive one.

How are sex-linked traits inherited? __________ Color-blindness (Xn) is a very common sex-linked trait and is recessive to normal vision (XN). More males have this disorder than females. XNXN = Normal Female XNXn = Carrier Female Xn. Xn = Color-blind Normal Male XNY = Female Xn. Y = Color-blind Male

How is color-blindness inherited? Cross a carrier female for colorblindness with a male that is normal for colorblindness. NX n n. Y X X What are the genotypes of the parents? _______X______ XN Xn What is the probability that one of their children will be colorblind? NX n X n n X 50% (2/4) X _____ Y XN Y X n. Y What is the probability of a son being colorblind? 50% (1/2) _______

How is color-blindness inherited? Cross a normal female and a colorblind male. What is the probability that their daughter will be a carrier? XN XN Xn. XNX n Y XN Y 100% (2/2)

What is your blood type? Do you know what your blood type is? How many possible blood types are there?

Are there only 2 alleles for each trait? Pg. 8 Multiple Alleles - A gene that has more than 2 ____ alleles (or forms of a gene). In other words, not just one dominant and one recessive allele (i. e. R and r). � Even though there may be three or more different alleles – remember that each person can only carry two alleles for each gene (or trait).

How is blood type determined? In human blood groups, there are three different alleles that determine the basic blood type. Type A and Type B (which are codominant) and Type O (which is recessive). • Your blood type is determined by which two alleles you inherit from your mom and your dad. These alleles tell your body what type of antigen to produce on your red blood cells (RBCs).

How is blood type determined? Antigens are molecules on the blood cells that are recognized by the immune system. Blood type A __ has only A antigens on their RBCs. B Blood type. AB __ has only B antigens Blood type O ___ has both A and B antigens Blood type __ does not have either A or B antigens.

How is blood type written? The following are symbols that are used for blood types: Blood Type (Phenotype) Genotype(s) Type. O __ ii Type. A__ IA I A or IA i Type B __ IB I B or IB i Type. AB __ IA I B

How is blood type inherited? Practice: Only the genotypes & phenotypes that appear in the punnett squares need to be written. 1. A man with type O blood marries a woman with type AB blood, what are the possible blood types of their children? Possible genotypes of offspring: i i IA i: 2/4 B i: 2/4 I A A I i I Possible phenotypes of offspring: IB IB i Type A= 2/4 Type B= 2/4

More Practice pg. 9 Is it possible for a man with type A blood and a woman with type B blood to have one child with type O blood another child with type AB Blood? Why or why not? Show your work!!! IA i IB IA I B IB i ii i IA i YES it’s possible

Why does knowing your blood type matter? Sometimes when individuals lose too much blood due to a trauma or surgery, other blood can be given back to them. This is called a ________. transfusion

Why does knowing your blood type matter? antigen Due to the presence of the _____ on the red blood cells, it is extremely important that the correct blood type be given. antibodie unidentified antigens are present on a cell, immune _______ will attach to the antigens & s � If the _____ system will attack the foreign cell. � If the wrong blood is transfused, the antibodies will cause the blood to clump up, causing the individual to go into shock and possibly die.

Why does knowing your blood type matter? universal Type O is known as the _________. donor Since there are no antigens on the blood cells it can be given to someone with type A, B, AB or O. universal recipient Type AB is called the __________. A person with type AB blood could receive a transfusion of blood from any of the four blood types since its body would recognize both the A and B antigens.

Do you know your blood type? Are you positive? You may have heard blood type described as positive or negative. Why? Red blood cells may also have a second antigen Rh called. Factor ________. This trait is not caused by multiple alleles like the ABO blood groups, rather it is influence by simple complete dominance.

Do you know your blood type? Are you positive? positive allele causes people to Rh ______ produce the Rh antigen on their blood cells. (Dominant) negative Rh ______ allele DOES NOT provide the instructions for making a Rh antigen on the blood cells. (Recessive) A person that is AB+ has three antigens on their blood cells (A, B and Rh+).

How can we tell if someone has a genetic disorder? Some disorders are caused by specific genes, other disorders are caused by a mess-up in the number of your full chromosomes. When we are looking at those types of disorders we can use a tool called a karyotype. Karyotype – a picture/chart of chromosome pairs.

What do normal karyotypes look like? Normal Male Karyotype Normal Female Karyotype

What are some ways that chromosomes can be messed up? Aneuploidy: having an abnormal number of chromosomes. -ex. Instead of having 46, you have 47 chromosomes. Trisomy: having 3 of a chromosome instead of 2

What are common examples of trisomy? Down Syndrome Trisomy 21 -Occurs when individuals have 3 copies of chromosome 21 instead of 2 -About 1 out of 800 people have this in the US -Symptoms: -Mental retardation -Short, stocky arms and legs -Characteristic facial features

What are common examples of trisomy? Klinefelters Syndrome -Occurs when males have more than one X chromosome -Instead of being XY, this male would be XXY or XXXY -About 1 out of 500 people have this in the US -Symptoms: -Learning disabilities -Infertility -Slight breast development

What are some ways that chromosomes can get messed up? Aneuploidy: having an abnormal number of chromosomes. -ex. Instead of having 46, you have 47 chromosomes. Monosomy: having 1 of a chromosome instead of 2

What is a common example of monosomy? Turner Syndrome -Occurs when females only get 1 X -About 1 out of 2, 500 people have this in the US -Symptoms: -Short stature -Infertility

Is there a way to find out if a baby will have a genetic disorder before it is born? YES! It is called amniocentesi s. is a procedure used to determine if a Amniocentesis fetus has a genetic disorder. In this procedure, a large needle is inserted into the abdomen of the mother and a sample of the amniotic fluid is taken. The cells of the fetus can be analyzed for any genetic disorders. One way to analyze the fetal cells