Genetics II Abnormal Meiosis Nondisjunction Disorders Cytoplasmic Inheritance

Let’s review some genetics terms…

Genetics Terms… Our body cells are also known as: A. somatic cells B. gametes

Genetics Terms… Our body cells are also known as: A. somatic cells B. gametes

Genetics Terms… Sperm and egg cells are: A. somatic cells B. gametes

Genetics Terms… Sperm and egg cells are: A. somatic cells B. gametes

Genetics Terms… Examples of human somatic cells are: A. skin cells, bone cells, nerve cells B. sperm cells, egg cells

Genetics Terms… Examples of human somatic cells are: A. skin cells, bone cells, nerve cells B. sperm cells, egg cells

Genetics Terms… Somatic cells are diploid, which means… A.They divide very quickly. B.They have two sets of chromosomes. C.They have one set of chromosomes.

Genetics Terms… Somatic cells are diploid, which means… A.They divide very quickly. B.They have two sets of chromosomes. C.They have one set of chromosomes.

Genetics Terms… Which of the following is true? A.Gametes are haploid. B.Gametes are diploid. C.Gametes are reproductive cells. D.Two of the above are true.

Genetics Terms… Which of the following is true? A.Gametes are haploid. B.Gametes are diploid. C.Gametes are reproductive cells. D.Two of the above are true.

Genetics Terms… Which of the following is true? Homologous chromosomes… A. are similar in size and shape B. are found in gametes C. are found in somatic cells D. separate during Anaphase II E. Two of the above are true.

Genetics Terms… Which of the following is true? Homologous chromosomes… A. are similar in size and shape B. are found in gametes C. are found in somatic cells D. separate during Anaphase II E. Two of the above are true.

Now let’s look at meiosis again…

What kinds of errors can happen during meiosis?

Nondisjunction can happen during Anaphase I or during Anaphase II results in gametes can have too many or too few chromosomes can also happen in mitosis, but this is less harmful because it isn’t passed on to the next generation

Chromosomal Disorders wrong number of chromosomes or changes (mutations) in the genetic information

Karyotype - male or female?

Down syndrome (trisomy 21)

Down Syndrome affects about 1 in 800 babies varying degrees of intellectual disability characteristic facial features often have heart defects and other problems

Trisomy 13

Trisomy 18

Trisomy 13 & Trisomy 18 1 in babies are born with trisomy 13 and 1 in 5000 are born with trisomy 18 severe intellectual disabilities many physical birth defects most affected babies die before their first birthday

Klinefelter syndrome

affects about 1 in boys usually have normal intelligence but many have learning problems as adults they produce less than normal amounts of testosterone and are infertile

Turner syndrome

Turner syndrome (monosomy 23) affects 1 in 2500 girls usually infertile and do not undergo normal puberty changes unless they are treated with hormones some have health problems including heart and kidney defects normal intelligence but some have learning difficulties

Triple X

affects 1 in 1000 females usually no physical birth defects, experience normal puberty and are fertile usually have normal intelligence but many have learning problems

XYY

affects 1 in 1000 males sometimes taller than average, have normal sexual development and are fertile most have normal intelligence, though some have learning, behavioral and speech/language problems

Assisted Reproductive Technologies (ARTs)

ARTs in vitro fertilization (IVF) artificial insemination

Applications & Implications animal breeding & wildlife conservation many benefits to using artificial insemination cost?

Cytoplasmic Inheritance

Cytoplasmic DNA DNA in mitochondria and chloroplasts When a sperm cell fertilizes an egg cell, which cell contributes the cytoplasmic DNA? maternal inheritance paternal inheritance (less common)

Genetic Variation - Plants normal green chloroplasts white chloroplasts with genetic mutation

Genetic Variation - Humans some rare genetic disorders caused by mutations in mitochondrial DNA DNA egg swapping

Horizontal Gene Transfer