Genetic Traits TEKS 7.14A: The student will define heredity as the passage of genetic instructions from one generation to the next generation. What is a trait? A trait is a behavioral characteristic or physical attributes of an organism that are expressed by genes and/or influenced by the environment.

Bill Nye Science Guy - Genes http://www.youtube.com/watch?v=MEHsLpq7bcY How Stuff Works? – The Future of Genetic Modification http://www.bing.com/videos/search?q=human+genetic+traits&FORM=HDRSC3#view=detail&mid=9E64BC365FAB6D5453669E64BC365FAB6D545366 Neil deGasse Tyson – NOVA, Explains why twins are not identical http://www.bing.com/videos/search?q=NOVA+genetics&FORM=HDRSC3#view=detail&mid=0D98A118A88A4088A9FE0D98A118A88A4088A9FE

Bill Nye the science guy - genes http://www.bing.com/videos/search?q=Heredity+Science+Olympiad&Form=VQFRVP#view=detail&mid=40F8929CF8BA8E413EF140F8929CF8BA8E413EF1

Pbs/NOVA - cracking your genetic code http://www.bing.com/videos/search?q=Nova+Heredity&Form=VQFRVP#view=detail&mid=C09A6737C9624C4B2F03C09A6737C9624C4B2F03 Neil degrasse tyson – nova, personal dna testing using saliva to find diseases http://www.bing.com/videos/search?q=Nova+genetic+testing&FORM=HDRSC3#view=detail&mid=9824DBD0CE82230C4CC29824DBD0CE82230C4CC2

What is a trait?

Genetic Traits (post-homework) Where did these traits come from? From your biological parents. One set of chromosomes from your mom (23) and one set of chromosomes from your dad (23). Which make a total of 46 chromosomes (23 pairs). http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/K/Karyotype.html http://www.biologycorner.com/worksheets/Chromosomestudy.htm Prokaryote vs. Eukaryote cells? Remember? Prokaryotic (Archaebacteria, Bacteria, and some protists) do not have genetic material contained in a nucleus, but the genetic material is still present. Eukaryotic (other Protists, Fungi, Plants, and Animals) have genetic material contained in the nucleus.

What is a Gene? A gene is a segment of DNA located on each chromosome. Each gene has a particular form. The genetic material is made of an organic compound called deoxyribonucleic acid (DNA).

Chromosomes are found in each living organisms cells they contain the hereditary material. In Eukaryotes, chromosomes are found in the nucleus. Heredity is the passing on of a trait contained in chromosomes to the next generation.

What elements does an organic compound contain? CARBON, and hydrogen, oxygen, nitrogen, phosphorus, and sulfur. SPONCH

An allele can either be dominant or recessive. Within the nucleus, genes occur in pairs. An allele is a form of a gene. An allele can either be dominant or recessive. If a dominant allele of a gene is present, the dominant trait will appear (show the phenotype) in an organism. A capital letter is used to represent a dominant allele. (Rr, RR)

In order for a recessive trait to appear (show the phenotype), both alleles of a gene must be recessive. A lower case letter is used to represent a recessive allele. (rr) These 4-square examples are called Punnett Squares and used by geneticists.

FYI: The work of gregor mendel was based on his discovery that heredity information for two different forms of a trait can coexist in one individual. He recognized that one form of the trait masks the expression of the other. This principle is known as the Law of dominance. http://www.bing.com/videos/search?q=gregor+mendel&FORM=HDRSC3#view=detail&mid=97EF05F36E3622FBD2F697EF05F36E3622FBD2F6 The Father of Modern Genetics http://www.bing.com/videos/search?q=gregor+mendel&FORM=HDRSC3#view=detail&mid=0CD8E58343E97CCDE4FF0CD8E58343E97CCDE4FF

Scientists use a model called a Punnett Square to predict the outcome of a particular combination of parent traits. They predict the potential genotypes of the offspring of two parents with known genotypes.

The genotype is the possible combinations of alleles in a gene. The expression of a gene is called a phenotype. (photo – what you see) The genotype is the possible combinations of alleles in a gene.

TEKS 14C: The students recognize that inherited traits of individuals are governed in the genetic material found in the genes within chromosomes in the nucleus.

Complete handout: “How do genes determine traits?” And / or Complete “Penny genetics” lab.

TEKS 14B: The students compare the results of uniform or diverse offspring from sexual reproduction or asexual reproduction.

The prefix a- means without; the root word “sexual” implies the union of an egg and sperm cells (two parents).

Asexual reproduction advantage is that it does not involve finding a mate; offspring occur quickly. The disadvantage is that all of the offspring have the same genetic makeup as the parent. There is NO diversity.

In sexual reproduction, genetic material is donated from two parents and the offspring have more genetic variation.