inheriting trait heredity is the passing of traits from parent to offspring genetics is the study...
TRANSCRIPT
Inheriting Trait Heredity is the passing of traits from
parent to offspring Genetics is the study of how traits are
inherited through the interactions of alleles
Alleles are the different forms of a trait that make up a gene pair Alleles separate in the sex cells during
meiosis and results with one allele is being donated by each parent for the traits they carry
Gregor Mendel, 1856, Austrian monk studied how traits were transferred to offspring
Studied pea plants and 7 traits Used scientific method and
mathematics to predict offspring traits
When plants always produce the same traits generations and generation they are called purebreds
He noticed when he crossed purebreds with different traits they always produce one of the traits by one parent. He called these hybridsFor example: crossed purebred tall
pea plants with purebred short pea plants and always got tall plants
Cross pollination techniques allowed Mendel to cross the tall and short purebreds
The result was always tall plants Mendel called the tall form the
Dominate factor while the short form was called Recessive factor
In the first generation the short trait disappeared , while the tall trait dominated over the short
Punnett square is a tool to help predict the possible outcomes of traits
Mendel used capital letters to represent each allele that were dominate (TT) representing tall purebred .
He used small letters for the same alleles that were recessive(tt) short plants
Two alleles that are the same are called homozygous (both above are homozygous)
Heterozygous refers to an organisms with 2 different alleles Tt
Tt represents a crossbred plant with one allele (Tall) and one allele (short)The offspring is tall because the tall allele dominates over the short
Genotype is the genetic make up of an organism
TT, tt and Tt represents the genetic make up of pea plants dealing with tall and short plants Actual alleles present in an organisms
Phenotype represents the actual appearance of the offspring TT would appear tall, Tt would appear
tall, tt would appear short
On the top of square, one parent has both alleles above the square, one each in each section
The vertical side has one parent has both alleles, one each in each section
Each square in grid is filled with one allele from each parent
Probability of offspring can be calculated
1. traits are controlled by alleles on chromosomes
2. An allele’s effect is dominant or recessive
3. When a pair of chromosomes separates during meiosis, the different alleles for a trait move into separate sex cells
When 2 homozygous parent show intermediate phenotypes it is called Incomplete Dominance
Occurs when some pure white flowers cross with pure red flowers and phenotype of offspring is pink
When cross the pink flowers, the result was some pink, white and red flowers on 2nd generation
Some traits are determined by more than 2 alleles
A trait that is controlled by more than two alleles is said to be controlled by multiple alleles
Traits controlled by multiple alleles produce more than three phenotypes
Blood type is determined by 3 allelesA, B, O blood allelesO is recessive homozygous OOAB both A and B is expressedA blood type could be AA, or AOB blood type could be Bb or BO
Groups of gene pairs acts together to produce a trait
Effect of many genes acting on a trait effect a wide variety of phenotypes
Eye color, height, skin color are examples
Chromosomes disorders can occur because of wrong numbers of chromosomes produced during meiosis
Down syndrome is a result of 3 copies of chromosome 21
In order for a recessive disorder to show up, both parents may have the hidden recessive gene but not shown in one or either parent
Cystic fibrosis is homozygous recessive disorder Disorder produces thick mucus in
lungs that make it hard to breath
Females are designated XX(both alleles for sex are the same)
Males XY (X or Y alleles can be donated )
Sex linked gens is an allele on a sex chromosome
Color blindness is a recessive disorder caused on X allele Female would be color blind if both X alleles
are present Male will be color blind if the X allele is
present Males most generally are color blind
http://www.youtube.com/watch?v=yEIM4jmK1F0&feature=related
Dominate sex linked disorders are rare and result when a person inherits at least on dominant sex linked allele Vitamin D rickets is an example where kidneys
can’t absorb adequate amounts of phosphorus leading to soft bones, teeth
Represent a tool to follow traits of family Squares represent male Circles represent females Affected traits are colored in You can follow traits thru family history
and compare if it is a sex linked
Genetic engineering is the experimenting with biological and chemical methods to change the DNA that makes up a gene
Help in medicine, genetic crops have been completed with genetic engineering
Recombinant DNA: inserting a useful segment of DNA from one organism into bacteriumInsulin for diabetics is a result of recombinant DNA
Gene Transfer: replace abnormal genetic material with normal genetic material
Genetically Engineered Plants: finding the genes that produce desired traits in one plant and inserting those into a different plant