Forming a New Life PDF

Forming a New Life Fertilization conception process by which sperm and ovum-the male and female gametes, or sex cells- combine to create a single cell called zygote Assisted Reproductive Technologies conception through artificial means couples having difficulty conceiving...

Forming a New Life Fertilization conception process by which sperm and ovum-the male and female gametes, or sex cells- combine to create a single cell called zygote Assisted Reproductive Technologies conception through artificial means couples having difficulty conceiving naturally success rates of only 23.6% of any single trial of ART resulted in successful pregnancy in 2019 Assisted Reproductive Technologies artificial insemination in vitro fertilization (IVF) sperm is injected into woman’s ova surgically removed, a woman’s vagina, fertilized in laboratory dish, and cervix or uterus implanted in the woman’s uterus cryopreservation, or egg freezing extend years of fertility eggs are harvested with intention of conceiving a child at a later date with the help of IVF Multiple births twins triplets quadruplets dizygotic twins monozygotic twins fraternal twins cleaving of one fertilized two separate eggs fertilized by egg and are genetically two different sperms to form two identical unique individual result of the interaction tend to run in the families between genes and result of multiple eggs being environmental influences released at one time Influences of Multiple births trend towards delayed childbearing increased use of fertility drugs, which spur ovulation, and of assisted reproductive techniques such as in vitro fertilization, which tend to be used by older women Mechanisms of Heredity Mechanisms of Heredity The Genetic Code Deoxyribonucleic acid Genetic code - sequences of (abbreviated DNA) - chemical bases within the DNA that carries inherited molecule; governs the instructions for the formation of proteins that development of all cellular determine the structure and forms of life functions of living cells Mechanisms of Heredity The Genetic Code chromosomes Genes coils of DNA that consists functional units of heredity of smaller segments Human genome complete sequence of genes in the human body Mechanisms of Heredity The Genetic Code every cell in the normal body has 23 pairs of chromosomes - 46 in all except the sex cells (sperm and ova) meiosis - type of cell division that sex cells undergo when they are developing each sex cells ends up with only 23 chromosomes - one from each pair Mechanisms of Heredity The Genetic Code sperm and ovum fuse at conception, produce a zygote with 46 chromosomes 23 from father and 23 from the mother mitosis - process by which the non sex cells divide in half over and over again DNA replicates itself; newly formed cells has the same DNA structure as the other Mechanisms of Heredity The Genetic Code mutation mistake in copying permanent alterations in genes or chromosomes that may produce harmful characteristics Mechanisms of Heredity Sex Determination autosomes sex chromosomes twenty-two pairs of our 23 twenty-third pair chromosomes one from the father and one not related to sexual expression from the mother traits governs baby’s sex Mechanisms of Heredity Sex Determination genetic male genetic female an ovum (X) is fertilized by a Y- ovum (X) is fertilized by an X- carrying sperm carrying sperm zygote is XY zygote is XX sex chromosome of every ovum is an X chromosome sperm may contain either X or Y chromosome Mechanisms of Heredity Patterns of Genetic Transmission Gregor Mendel laid the foundation for our understanding of patterns of inheritance in 1860s First, traits could be either dominant or recessive Second, traits are passed down independently of each other Mechanisms of Heredity Patterns of Genetic Transmission alleles genes that can produce alternative expression of characteristics alternative versions of same genes every person receives one from mother and one from father located on a chromosome Mechanisms of Heredity Patterns of Genetic Transmission homozygous heterozygous alleles are the same alleles are different Mechanisms of Heredity Patterns of Genetic Transmission dominant inheritance recessive inheritance dominant allele is always person must have two recessive expressed alleles shows up as a trait in that person one from each parent person will look the same if expressed, that person cannot whether or not he or she is have a dominant allele heterozygous or homozygous because recessive allele doesn’t show Mechanisms of Heredity Patterns of Genetic Transmission polygenic inheritance interaction of several genes ex. there is not intelligence gene that determines whether or not you are smart large number of genes work in concert to determine your intellectual potential Mechanisms of Heredity Multifactorial Transmission combination of genetic and environmental factors to produce certain complex traits environmental experience modifies the expression of the genotype for most traits illustrates the interaction of nature and nurture and how they affect outcomes Mechanisms of Heredity Multifactorial Transmission phenotype genotype observable characteristics underlying genetic make through which genotype is up expressed genetic code physical expression contributes to phenotype Mechanisms of Heredity Epigenetic Influences on Gene Expression epigenesis mechanism that turns genes on or off and determines functions of body cells works via chemical molecules, or “tags, attached to a gene that affect the way a cell “reads” function of the chemical tags is to differentiate various types of body cells Mechanisms of Heredity Genetic and Chromosomal Abnormalities defects transmitted by dominant inheritance are less likely lethal at an early age than those transmitted by recessive inheritance any affected children would likely to die before reproducing recessive defects are expressed only if the child is homozygous for that gene Mechanisms of Heredity Genetic and Chromosomal Abnormalities a child must inherit a copy of the recessive gene from each parent defects transmitted by recessive genes tend to be lethal at an earlier age recessive genes can be transmitted and are able to reproduce and pass the genes down to the next generation Mechanisms of Heredity Genetic and Chromosomal Abnormalities Mechanisms of Heredity Genetic and Chromosomal Abnormalities incomplete dominance pattern of inheritance in which a child receives two different alleles results in partial expression of a trait ex. child of parents each with curly hair and straight hair will always have wavy hair Carriers of Tay-Sachs disease exhibit incomplete dominance. Mechanisms of Heredity Sex-Linked Inheritance of Defects sex-linked inheritance  chromosomes is smaller and carries far fewer Y genes that X chromosomes males receives only one copy of any gene that happens to be carried on the sex chromosomes, while female receives two copies ex. if a woman has a “bad” copy of particular gene, she has a back up copy Mechanisms of Heredity Sex-Linked Inheritance of Defects sex-linked inheritance if a male has a “bad” copy of a particular gene, that gene will be expressed Mechanisms of Heredity Chromosomal Abnormalities chromosomal Abnormalities typically occur because of errors in cell division results in extra or missing chromosomes likelihood of errors increase in offspring of women age 35 or older Mechanisms of Heredity Chromosomal Abnormalities down syndrome characterized by moderate-to-severe intellectual disability physical signs as a downward-slopping skin fold at the inner corner of eyes also called trisomy-21; characterized in more than 90% of cases by an extra 21st chromosome most common chromosomal abnormality Mechanisms of Heredity Karyotype of a female with Down Syndrome Mechanisms of Heredity Genetic Counseling and Testing genetic counseling clinic service that advises prospective parents of their probable risk of having children with hereditary defects help prospective parents assess their risk of bearing children with genetic or chromosomal defects genetic counselor takes family history and gives prospective parents and any biological children physical examination may be performed by investigating blood, skin, urine or fingerprints Studying the Influences of Heredity and Environment Measuring Heritability behavioral genetics heritability quantitative study of relative estimating how much of a hereditary and environmental trait is due to genetics and influences of behavior how much is the result of seeks to measure how much heredity and environment environmental influences influence particular traits Studying the Influences of Heredity and Environment Measuring Heritability concordant term describing tendency of twins to share the same trait or disorder the same on a given trait