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Aim: How are human traits inherited?. HW #9 Chapter 14 text Read pages 340-343 Construct a pedigree of your family starting with your grandparents showing how a particular trait is expressed. Include a key. Pedigree Chart. Poll the class to determine what traits are present.
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Aim: How are human traits inherited? HW #9 Chapter 14 text Read pages 340-343 Construct a pedigree of your family starting with your grandparents showing how a particular trait is expressed. Include a key.
There are no pairs of chromosomes in the sperm or egg of sexually reproducing organisms. Fertilization restores the 2n number, each parent contributing one chromosome to restore the pair.
Figure 14-3 A Pedigree Human Pedigree Chart Section 14-1 A circle represents a female. A square represents a male. A vertical line and a bracket connect the parents to their children. A horizontal line connecting a male and female represents a marriage. A half-shaded circle or square indicates that a person is a carrier of the trait. A circle or square that is not shaded indicates that a person neither expresses the trait nor is a carrier of the trait. A completely shaded circle or square indicates that a person expresses the trait. Go to Section:
Codominant alleles Recessive alleles Dominant alleles Tay-Sachs disease Huntington’s disease Sickle cell disease Galactosemia Albinism Cystic fibrosis Hypercholes- terolemia Phenylketonuria Achondroplasia Concept Map recessive, dominant or co-dominant alleles on one of the 22 pairs of chromosomes Section 14-1 Autosomol Disorders caused by include include include Go to Section:
Dominant Allele on chromosome 4 • The clinical features of achondroplasia include the following: • Short stature • Rhizomelic (proximal) shortening of the arms and legs with redundant skin folds on limbs • Limitation of elbow extension • Trident configuration of the hands • Genu varum (bow legs)
Traits can be carried on Autosomal chromosomes (1 – 22) Or The sex chromosomes (X, Y)
Anyone with 40 or more CAG repeat sequences will develop HD and their children will have a 50 per cent risk of developing HD. Evidence suggests that the huntingtin protein in people with HD tends to break into pieces, which then clump together. These protein clumps build up inside the nuclei of brain cells, which either impairs their functioning or kills them. HD is an autosomal dominant condition
Aim: How are Sex-linked Traitsinherited in the Human Population ?
Examples of Sex-linked Traits: Red-green colorblindness Male Pattern Baldness Hemophilia Duchenne Muscular Dystrophy
Hemophilia is a disorder caused by an error in a person’s genetic code. Carried on the X chromosome
Pedigree of Queen Victoria's Descendantsshowing a sex linked trait
The inheritance of Colorblindness Parent phenotypes: normal vision Father X colorblind Mother Genotypes: X Y Offspring phenotypes X X
Parents’ phenotypesNormal Vision Father X Normal vision Mother(no colorblindness Mother' family) Parents’ Genotype: Offspring Phenotypes X Y X X