Chapter 29 - Development and Inheritance PART 2 Flashcards
What is Inheritance?
Passage of hereditary traits from one generation to next
Humans have 23 pairs of homologous chromosomes
One pair from father, one from mother
What is Allele?
Alleles:
Genes for same trait that are used in same location on each homologue
What is Mutation?
Permanent heritable change in an Allele
ex:
Phenylketonuria (PKU)
People with PKU cannot make the enzyme Phenylalanine Hydroxylase which is needed to break Phenylalanine
Punnett Square:
Shows possible genes inherited from 2 parents
What is Genotype?
Actual genetic makeup relating to a trait
What is Phenotype?
Physical expression of the Genotype
What are some Dominant vs Recessive Hereditary Traits?
Dominant vs Recessive:
1- Normal skin pigmentation - Albinism
2- Near/Farsightedness - Normal vision
3- PTC taster - PTC non-taster
4- Polydactyly - Normal digits
5- Brachydactyly (short) - Normal digits
6- Syndactyly (webbed) - Normal digits
7- Diabetes Insipidus - Normal urine excretion
8- Huntington Disease - Normal nervous system
9- Widow’s Peak - Straight hairline
10- Curved (Hyperextended) Thumb - Straight thumb
11- Normal CI Transport - Cystic Fibrosis
12- Hypercholesterolemia (familial) - Normal Cholesterol level
What is Inheritance Pattern?
Most patterns of inheritance don’t conform to Dom/Rec inheritance pattern
Incomplete Dominance:
Neither member of pair of Alleles is dominant over other
ex: Sickle Cell Anemia
What is Multiple-Allele Inheritance?
Occurs when genes have more than 2 alternative forms
ex:
Inheritance of ABO Blood Group
Codominance:
2 Genes expressed equally
ex: Type A and Type B blood
What is Polygenic Inheritance?
Seen when a trait is controlled by the combined effect of 2 or more genes
What is Complex Inheritance?
Seen when a trait occurs due to the combined effects of many genes and environmental factors
ex:
Skin color
Hair color
Eye color
Height
Metabolic rate
Body build
What is Karyotype?
Karyotype:
Entire set of chromosomes arranged in decreasing size order and according to the position of the centromere
The 46 human chromosomes (23 pairs) are identified by their size, shape, and staining pattern
What is Chromosome?
23 pairs:
22 pairs of Autosomes
1 pair of Sex Chromosomes (X and Y)
Male: XY
Female: XX (one is automatically inactivated)
What is Sex-Linked Trait?
Non-sexual Traits that are inherited on the X Chromosome
ex:
Red-green color blindness
What are some Inheritance Disorders?
1- Infertility
2- Congenital Defects
3- Down Syndrome
