Heredity & Societies Transmission Genetics (Lectures 4-6) Flashcards
Why did Mendel use peas?
Identifiable traits Easy to grow Take little space Inexpensive Short growth period Self fertilizing Artificially fertilized
Who is Johan Gregor Mendel
- monk
- expired mended peas to understand fundamental principles of genetics
What was mendle’s experimental design?
Large sample size over 10 yr period 7 different traits Repeated experiments Analyzed data with probability and statistics Lack of preconceived notion
Allele
Alternate form or variation of gene
2 types of alleles
Homozygous and heterozygous
Homozygous
Two identical alleles for a gene
Heterozygous
Two different alleles for a gene
Phenotype
Physical trait of an organism; obserable
Genotype
Genetic constitution of an organism
Dominant
The allele that the organism’s appearance
Recessive
alleles that has no noticeable effect on the appearance
Mendel’s first law
Principle of segregation
- members of a gene pair separate during the formation of gametes
- genes must separate during gametes formation so that each game contributes one gene to the zygote
Mendel’s Second Law
Principle of Independent Assortment: alleles of one pair of genes segregate into gametes independent of the alleles from another gene pair. Genes are packaged into gametes randomly
Mendelian inheritance in humans pigmentation gene and albinism
75% normals
25% albino
What is albinism
Pigmentation dominant and lack of pigment recessive 3:1 ratio
Where are autosomal traits located?
Human autosomal traits are located on the non sex chromosomes (1-22)
What are autosomal traits
They may be inherited as auto sales recessive or autosomal dominant. The non sex chromosomes
Pedigree
Depicts family relationships and patterns of inheritance for particular traits
Autosomal Recessive
- Unaffected parents have affected children
- All children of affected parents are affected
- Both parents Aa, risk affected child -25%
- Equal affected male and female
- consanguinity
Consanguinity
Kissing cousins